Printing method of electrode structure of back contact battery

Abstract

The invention relates to the technical field of semiconductors, and discloses a printing method of an electrode structure of a back contact battery, which comprises the following steps: providing a back contact battery which comprises a front surface and a back surface which are oppositely arranged; a main grid region and an auxiliary grid region are arranged on the back surface of the back contact battery; printing corrosive slurry on the surface of the auxiliary grid region and the surface of the main grid region, and printing non-corrosive slurry on the surface of the main grid region; wherein the non-corrosive slurry on the surface of the main grid region is at least located at the side part of the corrosive slurry; and forming an electrode structure after annealing and sintering, wherein the electrode structure comprises a main gate electrode positioned in the main gate region and an auxiliary gate electrode positioned in the auxiliary gate region. According to the invention, the current carriers in each region of the silicon substrate can be fully collected while the gold / semi-composite area is reduced, the utilization rate and collection efficiency of the current carriers are improved, and thus the electrical performance of the cell is improved.

Description

Technical Field

[0001] This disclosure relates to the field of semiconductor technology, and more specifically to a method for printing an electrode structure for a back contact battery. Background Technology

[0002] Compared to conventional batteries, back-contact batteries significantly improve optical performance by moving the front grid lines to the back, forming a full-back interdigitated contact structure. The rationality of the back grid patterning scheme is crucial to the battery's performance. Conventional back-contact batteries typically use a main grid paired with a sub-grid to form a "tree-like" structure. However, this structure has significant drawbacks. First, the main grid is often quite wide and generally uses a non-corrosive or low-corrosion paste to avoid burning through the bottom passivation and anti-reflection film, serving only as a current collector. This results in insufficient collection of charge carriers within the silicon substrate at the bottom of the main grid. Second, if the main grid uses a corrosive paste, the gold / semi-reflective composite area in that region becomes too large, still limiting carrier collection performance.

[0003] Therefore, a solution is needed to fully collect charge carriers in the silicon substrate corresponding to each region of the back contact battery, thereby improving battery performance. Summary of the Invention

[0004] This disclosure provides a method for printing the electrode structure of a back contact battery to solve the problem in related technologies where the main grid uses a non-corrosive or low-corrosive paste, resulting in insufficient collection of charge carriers in the silicon substrate at the bottom of the main grid.

[0005] In a first aspect, this disclosure provides a method for printing an electrode structure for a back-contact battery, the preparation method comprising: A back contact battery is provided, which includes a front side and a back side arranged opposite to each other; the back side of the back contact battery is provided with a main grid area and a sub-grid area; A corrosive paste is printed on the surface of the sub-gate region and the surface of the main gate region, and a non-corrosive paste is printed on the surface of the main gate region; wherein the non-corrosive paste on the surface of the main gate region is located at least on the side of the corrosive paste. After annealing and sintering, an electrode structure is formed, which includes a main gate electrode located in the main gate region and a sub-gate electrode located in the sub-gate region.

[0006] Beneficial Effects: The electrode structure printing method for the back contact battery provided in this disclosure, on the one hand, prints an etchant on the surface of the sub-gate region and the main gate region, enabling the main gate electrode and sub-gate electrode formed after annealing and sintering to fully collect charge carriers from various regions of the silicon substrate, thereby improving the utilization rate and collection efficiency of charge carriers. On the other hand, the non-etchant printed on the surface of the wider main gate region is located at least on the side of the etchant, which can reduce the gold / semi-composite area of ​​the main gate region and simultaneously reduce the line resistance of the gate lines, reducing the resistive loss of charge carriers in the gate lines, further improving the charge carrier collection performance, and thus improving the electrical performance of the battery. Therefore, the electrode structure printing method for the back contact battery provided in this disclosure can, while reducing the gold / semi-composite area, fully collect charge carriers from various regions of the silicon substrate, improve the utilization rate and collection efficiency of charge carriers, and thus improve the electrical performance of the battery.

[0007] In one optional embodiment, the steps of printing an etchant on the surfaces of the sub-gate region and the main gate region, and printing a non-etchant on the surface of the main gate region, include: Etching paste is printed simultaneously in the main grid area and the sub-grid area on the back side of the contact surface; A non-corrosive paste is overlaid on the surface of the main grid area, covering the surface and sides of the corrosive paste.

[0008] Beneficial Effects: The electrode structure printing method for the back contact battery provided in this disclosure first prints an etchable sub-gate paste at the bottom of a predetermined area (i.e., the main gate region) of the main gate electrode, and then prints a non-etchable paste on top of it, so that the non-etchable paste coats the etchable paste. On the one hand, the formed main gate electrode structure can fully collect carriers from the silicon substrate corresponding to the main gate region, and can also reduce the gold / semi-reinforced composite area; on the other hand, the formed main gate electrode has a "pagoda" shaped structure, which, due to its uneven top morphology, is more conducive to the absorption of incident light and improves light utilization. At the same time, the printing method has simple process steps, requiring only one process to print the etchable paste in both the main gate region and the sub-gate region simultaneously, without adding any additional process steps, which can improve printing process efficiency. In addition, the non-etchable paste often has high stability, and its coating of the etchable paste can also prevent the etchable paste from being severely oxidized by external air.

[0009] In one optional embodiment, the steps of printing an etchant on the surfaces of the sub-gate region and the main gate region, and printing a non-etchant on the surface of the main gate region, include: Non-corrosive paste is printed in the main grid area on the back of the battery. A groove is formed on the surface of the non-corrosive slurry; the groove penetrates the non-corrosive slurry and exposes the bottom main grid area; Corrosive paste is printed simultaneously in the groove and on the surface of the sub-grid area.

[0010] Beneficial effects: The electrode structure printing method for the back contact battery provided in this disclosure first prints a non-corrosive sub-gate paste across the entire main gate area, and forms a groove in the middle section. Finally, a corrosive paste is printed simultaneously inside the groove and on the surface of the sub-gate area. The resulting main gate electrode has a structure with a corrosive paste in the middle and a non-corrosive paste on the sides, which can effectively collect carriers from the silicon substrate corresponding to the main gate area and reduce the gold / semi-reinforced composite area. Simultaneously, this printing method can reduce the amount of non-corrosive paste used, thus lowering costs.

[0011] In one optional embodiment, the back side of the back contact battery includes a first doped region and a second doped region alternately spaced along a first direction; the first doped region includes a first main gate region and a first sub-gate region; the second doped region includes a second main gate region and a second sub-gate region; each first main gate region intersects with a plurality of parallel first sub-gate regions, and each second main gate region intersects with a plurality of parallel second sub-gate regions. The first sub-gate region and the second sub-gate region are arranged alternately along the second direction and both extend along the first direction; the first main gate region and the second main gate region are arranged alternately along the first direction and both extend along the second direction; the first direction is perpendicular to the second direction.

[0012] In one optional embodiment, the steps of printing an etchant on the surfaces of the sub-gate region and the main gate region, and printing a non-etchant on the surface of the main gate region, include: The first corrosive paste is printed simultaneously in the first main grid area and the first sub-grid area; The second corrosive paste is printed simultaneously in the second main grid area and the second auxiliary grid area; Non-corrosive paste is superimposed and printed in the first and second main grid areas, covering the surfaces and sides of the first and second corrosive pastes.

[0013] Beneficial effects: The electrode structure printing method of the back contact battery provided in this disclosure firstly prints a first etchable paste in the first main gate region and the first sub-gate region simultaneously, and then prints a second etchable paste in the second main gate region and the second sub-gate region simultaneously. Finally, a non-etchable paste is superimposed and printed in the first main gate region and the second main gate region. The non-etchable paste covers the surface and side of the first and second etchable pastes, forming a "pagoda" shaped structure with an uneven top morphology, which is beneficial to the absorption of incident light and improves the light utilization rate of the back contact battery. At the same time, the non-etchable paste in the first and second main gate electrodes covers the etchable paste, which can fully collect the carriers of the silicon substrate corresponding to the main gate region and reduce the gold / semi-composite area.

[0014] In one optional embodiment, the steps of printing an etchant on the surfaces of the sub-gate region and the main gate region, and printing a non-etchant on the surface of the main gate region, include: Non-corrosive paste is printed simultaneously in the first and second main grid areas on the back of the battery. Grooves are formed on the non-corrosive slurry surface in both the first and second main grid regions; the grooves penetrate the non-corrosive slurry and expose the bottom of the first or second main grid region. The first corrosive paste is simultaneously printed in the groove corresponding to the first main gate area and on the surface of the first sub-gate area; A second corrosive paste is simultaneously printed in the groove corresponding to the second main grid area and on the surface of the second sub-grid area.

[0015] Beneficial Effects: The electrode structure printing method for a back-contact battery provided in this disclosure firstly prints a non-corrosive paste simultaneously on a first main gate region and a second main gate region on the back side of the back-contact battery. Secondly, grooves are formed on the surfaces of the non-corrosive paste in both the first and second main gate regions. The grooves penetrate the non-corrosive paste and expose the bottom of the first or second main gate region. Finally, a first corrosive paste is simultaneously printed in the groove corresponding to the first main gate region and on the surface of the first sub-gate region; and a second corrosive paste is simultaneously printed in the groove corresponding to the second main gate region and on the surface of the second sub-gate region. The formed first and second main gate electrodes both have a structure with corrosive paste in the middle and non-corrosive paste on the sides, which can fully collect carriers on the silicon substrate corresponding to the main gate region and reduce the gold / semi-composite area. At the same time, this printing method can reduce the amount of non-corrosive paste used, thus reducing costs.

[0016] In one alternative embodiment, the step of forming the electrode structure after annealing and sintering includes: After annealing the slurry in the first main gate region and the first sub-gate region, the first main gate electrode and the first sub-gate electrode are formed respectively. After annealing the slurry in the second main gate region and the second sub-gate region, a second main gate electrode and a second sub-gate electrode are formed respectively; both the first main gate electrode and the second main gate electrode belong to the main gate electrode; both the first sub-gate electrode and the second sub-gate electrode belong to the sub-gate electrode.

[0017] Beneficial effects: The electrode structure printing method of the back contact battery provided in this disclosure uses a first corrosive paste and a second corrosive paste in the first doped region and the second doped region, respectively. After annealing, the paste can pass through the passivation film to form ohmic contacts with the first doped region and the second doped region, respectively, effectively reducing the contact resistance of the first sub-gate electrode and the second sub-gate electrode.

[0018] In one alternative embodiment, the resistivity of the corrosive slurry in contact with silicon is less than 10 mΩ·cm.2 ; The resistivity of the non-corrosive slurry in contact with silicon is greater than or equal to 10 mΩ / cm. 2 .

[0019] Beneficial effects: The electrode structure printing method for the back contact battery provided in this disclosure has a resistivity of less than 10 mΩ·cm in contact between the corrosive paste and silicon. 2 This ensures that the main and secondary gate electrodes formed after annealing and sintering of the corrosive slurry can fully collect charge carriers from all regions of the silicon substrate, improving carrier utilization and collection efficiency. The resistivity of the non-corrosive slurry in contact with silicon is greater than or equal to 10 mΩ·cm. 2 This can reduce the gold / semi-composite area in the main grid region and simultaneously reduce the line resistance of the grid lines, thereby reducing the resistive loss of charge carriers in the grid lines and further improving the charge carrier collection performance, thus improving the electrical performance of the battery. At the same time, the use of non-corrosive slurry can reduce the risk of material degradation of the main grid electrode during long-term use, improve durability, and thus improve the reliability and lifespan of the back contact battery electrode structure.

[0020] In one optional embodiment, the back of the back contact battery is further provided with a plurality of PAD dot regions covering a portion of the main grid area, and the plurality of PAD dot regions are evenly distributed along the length direction of each main grid area; the width of the PAD dot regions is greater than the width of the main grid area. A corrosive paste is printed on the surfaces of the sub-gate region, the main gate region, and the PAD point region, and a non-corrosive paste is printed on the surfaces of the main gate region and the PAD point region; wherein the non-corrosive paste on the surface of the main gate region is at least located on the side of the corrosive paste; the non-corrosive paste on the surface of the PAD point region is at least located on the side of the corrosive paste. In the step of forming the electrode structure after annealing and sintering, the electrode structure also includes multiple PAD electrodes disposed in the main gate region.

[0021] Beneficial effects: The electrode structure printing method of the back contact battery provided in this disclosure, by using the same printing method in the PAD point area as the main grid area, ensures that the non-corrosive paste on the surface of the PAD point area is at least located on the side of the corrosive paste, and forms the PAD electrode after annealing and sintering. This allows the highly corrosive paste in the PAD point area to melt and pass through the passivation film, forming an ohmic structure with the silicon substrate at the bottom. This enables sufficient collection of charge carriers on the silicon substrate at the bottom of the PAD point area, improving the utilization rate and collection efficiency of charge carriers, thereby enhancing the electrical performance of the battery.

[0022] In one alternative embodiment, the four corners of the top view structure of the back contact battery are chamfered. The main gate area near the chamfered structure also includes a corner extension area; In the step of forming the electrode structure after annealing and sintering, the main gate electrode also includes a main gate extension electrode located in the corner region; the main gate extension electrode is disposed opposite to the outermost sub-gate electrode and does not contact it.

[0023] Beneficial effects: The electrode structure printing method for the back contact battery provided in this disclosure forms a main grid extension electrode in the corner extension region near the chamfered structure. The non-corrosive paste in the main grid extension electrode is located at least on the side of the corrosive paste. This method can effectively collect the charge carriers in the silicon substrate corresponding to the blank area near the chamfered structure, improve the utilization rate and collection efficiency of the charge carriers, and thus improve the electrical performance of the battery. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the specific embodiments of this disclosure or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1A It is a schematic diagram of the electrode structure of a back contact battery in related technologies; Figure 1B It is a schematic diagram of the cross-sectional structure of the main grid electrode of the back contact battery in related technologies; Figure 2 This is a schematic flowchart of a method for printing an electrode structure for a back contact battery according to an embodiment of the present disclosure. Figure 3 This is a schematic flowchart of a printing method using a corrosive paste and a non-corrosive paste according to Embodiment 1 of this disclosure; Figure 4A This is a schematic diagram of the structure for printing the first and second corrosive pastes according to Embodiment 1 of this disclosure; Figure 4B Is Figure 4A A schematic diagram of the cross-sectional structure of region A in the middle; Figure 5A This is a schematic diagram of the structure for printing non-corrosive paste according to Embodiment 1 of this disclosure; Figure 5B Is Figure 5A A schematic diagram of the cross-sectional structure of region A in the middle; Figure 6 This is a schematic flowchart of a printing method using a corrosive paste and a non-corrosive paste according to Embodiment 2 of this disclosure; Figure 7A This is a schematic diagram of the structure for printing non-corrosive paste according to Embodiment 2 of this disclosure; Figure 7BIs Figure 7A A schematic diagram of the cross-sectional structure of region A in the middle; Figure 8 This is a schematic diagram of the structure of forming a groove on the surface of a non-corrosive slurry according to Embodiment 2 of this disclosure; Figure 9A This is a schematic diagram of the structure for printing a first corrosive paste and a second corrosive paste according to Embodiment 1 of this disclosure; Figure 9B Is Figure 9A A schematic diagram of the cross-sectional structure of region A in the middle; Figure 10 This is a schematic diagram of the PAD region in a method for printing the electrode structure of a back contact battery according to an embodiment of the present disclosure. Figure 11A This is a schematic diagram of the formation of a first corrosive paste in the PAD region during a printing method of the electrode structure of a back contact battery according to an embodiment of the present disclosure. Figure 11A for Figure 10 A magnified view of region B in the middle; Figure 11B In a method for printing the electrode structure of a back contact battery according to an embodiment of the present disclosure, Figure 11A A schematic diagram of a structure in which a non-corrosive slurry is formed in the PAD region.

[0026] Figure label: 10. Silicon substrate; 11. First doped region; 12. Second doped region; 21. First main gate region; 22. Second main gate region; 31. First sub-gate region; 32. Second sub-gate region; 50. Groove; 60. PAD dot region; 70. Corner extension region; 81. First etchable paste; 82. Second etchable paste; 90. Non-etchable paste; 1. Main gate; 2. Sub-gate; 3. Blank area; 4. Doped region; 8. Etched paste; 9. Non-etchable paste. Detailed Implementation

[0027] The present disclosure will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present disclosure and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present disclosure are shown in the drawings, not the entire structure. All other embodiments obtained by those skilled in the art based on the embodiments of the present disclosure without inventive effort are within the scope of protection of the present disclosure.

[0028] In the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily obscuring the concepts of this disclosure. Various structural schematic diagrams according to embodiments of this disclosure are shown in the accompanying drawings. These drawings are not to scale, and some details are enlarged for clarity and may be omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from actual practices due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed. In the context of this disclosure, when a layer / element is referred to as being "on" another layer / element, the layer / element may be directly on the other layer / element, or there may be an intermediate layer / element between them. Additionally, if a layer / element is "on" another layer / element in one orientation, then when the orientation is reversed, the layer / element may be "below" the other layer / element.

[0029] Compared to conventional batteries, back-contact batteries significantly improve optical performance by moving the front grid lines to the back, forming a full-back interdigitated contact structure. The rationality of the back grid line patterning scheme is crucial in determining the battery's performance. Conventional back-contact batteries typically use a main grid combined with sub-grids to form a "tree-like" structure, such as... Figure 1A and Figure 1B As shown, the main gate 1 and the sub-gate 2 are located on the surface of the doped region 4. The sub-gate 2 is generally made of an etchable paste 8, which sintersects with the silicon substrate at the bottom to form an ohmic contact. The main gate 1 is made of a non-etchable paste 9 or a low-etchable paste. However, this structure also has obvious problems. First, the main gate is often wide and generally uses a non-etchable or low-etchable paste, so it does not burn through the passivation antireflection film at the bottom and only serves as a current collector. This makes it impossible to fully collect the carriers in the silicon substrate at the bottom of the main gate. Second, if the main gate is made of an etchable paste, the gold / semi-reflective composite area in this region will be too large, and the carrier collection performance will still be limited.

[0030] Therefore, a solution is needed to fully collect charge carriers in the silicon substrate corresponding to each region of the back contact battery, thereby improving battery performance.

[0031] like Figure 2 As shown, this embodiment provides a method for printing an electrode structure for a back contact battery, the preparation method including but not limited to steps S101 to S103.

[0032] Step S101: Provide a back contact battery, which includes a front side and a back side disposed opposite to each other; the back side of the back contact battery is provided with a main grid area and a sub-grid area.

[0033] Step S102: Print an etchant on the surface of the sub-gate region and the surface of the main gate region, and print a non-etchant 90 on the surface of the main gate region; wherein the non-etchant 90 on the surface of the main gate region is located at least on the side of the etchant.

[0034] Step S103: After annealing and sintering, an electrode structure is formed, which includes a main gate electrode located in the main gate region and a sub-gate electrode located in the sub-gate region.

[0035] In specific implementation, the main body of the back contact cell provided in step S101 is a silicon substrate, and a passivation film is disposed on the back side of the back contact cell; in some examples, the passivation film includes stacked AlO₂. x Dielectric films and SiN x Dielectric film. Subsequently, during the printing of an etchant onto the surfaces of the sub-gate and main gate regions, and the subsequent annealing and sintering process, the etchant melts and burns through the surface AlO₂. x and SiN x The dielectric film, along with the high-temperature melting of silver particles in the corrosive paste, undergoes recrystallization during cooling to form a silver-silicon alloy ohmic contact with silicon, thereby collecting charge carriers in both the main gate and sub-gate regions. Simultaneously, since the main gate width is greater than the sub-gate width, the non-corrosive paste 90 printed on the surface of the main gate region is located at least on the side of the corrosive paste, preventing an excessively large gold / semi-composite area. The non-corrosive paste 90 can be located only on the side of the corrosive paste, or it can be located on both the surface and side of the corrosive paste (i.e., coating the corrosive paste).

[0036] For the secondary gate electrode, a highly corrosive paste is required. During sintering, the secondary gate paste needs to penetrate the passivation and antireflection film on the silicon wafer surface and form a silver-silicon alloy with the silicon substrate surface to achieve ohmic contact and minimize contact resistance. Therefore, a highly corrosive paste is more effective in this process. If the corrosivity of the secondary gate paste is reduced, the above-mentioned process effects cannot be achieved. Furthermore, the sintering process of the secondary gate requires precise control of the etching depth to ensure minimal contact resistance; thus, a highly corrosive paste is more effective in this process.

[0037] For the main grid electrode, its main component needs to be a non-corrosive paste. As the main body for current collection and transmission, the main grid electrode requires high conductivity and mechanical stability. The main task of its paste is to ensure reliable connection with the sub-grid and external conductors, rather than penetrating deep into the material. Therefore, the main grid paste must avoid strong corrosivity to prevent damage to the metallization or passivation layer of the cell. The sintering of the main grid focuses more on conductivity and adhesion, and does not require strong corrosivity. Secondly, the main grid is usually located on the front of the cell and is directly exposed to the environment or encapsulation material. Using a weakly corrosive paste can reduce the risk of material degradation during long-term use and improve durability. In addition, at the module encapsulation end, the solder strips connecting the main grid may use different metals (such as copper or tin-plated copper). If a strong corrosive paste is used, it will cause electrochemical corrosion between different metals. Therefore, the corrosivity of the main grid paste needs to be controlled to ensure compatibility. The middle width of the main grid electrode formed in this disclosure is composed of a corrosive paste, which can fully collect the charge carriers of the silicon substrate corresponding to the main grid region while ensuring the performance of the main grid electrode.

[0038] Beneficial Effects: The electrode structure printing method for the back contact battery provided in this disclosure, on the one hand, prints an etchant on the surface of the sub-gate region and the main gate region, enabling the main gate electrode and sub-gate electrode formed after annealing and sintering to fully collect charge carriers from various regions of the silicon substrate, thereby improving the utilization rate and collection efficiency of charge carriers. On the other hand, the non-etchant 90 printed on the surface of the wider main gate region is located at least on the side of the etchant, which can reduce the gold / semi-composite area of ​​the main gate region and simultaneously reduce the line resistance of the gate lines, reducing the resistive loss of charge carriers in the gate lines, further improving the charge carrier collection performance, and thus improving the electrical performance of the battery. Therefore, the electrode structure printing method for the back contact battery provided in this disclosure can, while reducing the gold / semi-composite area, fully collect charge carriers from various regions of the silicon substrate, improve the utilization rate and collection efficiency of charge carriers, and thus improve the electrical performance of the battery.

[0039] In some optional implementations, the main gate region is a preset region of the main gate electrode; the sub-gate region is a preset region of the sub-gate electrode.

[0040] In some optional embodiments, the steps of printing an etchant on the surfaces of the sub-gate region and the main gate region, and printing a non-etchant 90 on the surface of the main gate region, include: Etching paste is printed simultaneously in the main grid area and the sub-grid area on the back side of the contact surface; A non-corrosive paste 90 is overlaid on the surface of the main grid area, covering the surface and sides of the corrosive paste.

[0041] In practice, firstly, corrosive paste is printed simultaneously in the main grid area and the sub-grid area, wherein the corrosive paste covers the entire sub-grid area and the middle part of the main grid area; secondly, non-corrosive paste 90 is superimposed and printed on the surface of the main grid area, and the non-corrosive paste 90 covers the surface and sides of the corrosive paste and covers the entire main grid area.

[0042] Beneficial Effects: The electrode structure printing method for the back contact battery provided in this disclosure first prints an etchable sub-gate paste at the bottom of a predetermined area (i.e., the main gate region) of the main gate electrode, and then prints a non-etchable paste 90 on top of it, so that the non-etchable paste 90 covers the etchable paste. On the one hand, the formed main gate electrode structure can fully collect carriers from the silicon substrate corresponding to the main gate region, and can also reduce the gold / semi-reinforced composite area; on the other hand, the formed main gate electrode has a "pagoda" shaped structure, which, due to its uneven top morphology, is more conducive to the absorption of incident light and improves light utilization. At the same time, the printing method has simple process steps, requiring only one process to print the etchable paste in both the main gate region and the sub-gate region simultaneously, without adding any additional process steps, which can improve printing process efficiency. In addition, the non-etchable paste often has high stability, and its covering of the etchable paste can also prevent the etchable paste from being severely oxidized by external air.

[0043] In other embodiments, when a non-corrosive paste 90 is overlaid on the surface of the main grid region, the non-corrosive paste 90 may only cover the sides of the corrosive paste.

[0044] In some optional embodiments, the steps of printing an etchant on the surfaces of the sub-gate region and the main gate region, and printing a non-etchant 90 on the surface of the main gate region, include: A non-corrosive paste 90 is printed in the main grid area on the back of the battery. A groove is formed on the surface of the non-corrosive slurry 90; the groove penetrates the non-corrosive slurry 90 and exposes the bottom main grid area; Corrosive paste is printed simultaneously in the groove and on the surface of the sub-grid area.

[0045] In practice, firstly, a non-corrosive paste 90 is printed in the main grid area, covering the entire main grid area; then, a groove is formed on the surface of the non-corrosive paste 90, located at the middle width of the main grid area; finally, a corrosive paste is printed simultaneously in the groove and on the surface of the sub-grid area, resulting in a main grid electrode with a corrosive paste in the middle and a non-corrosive paste 90 on the sides.

[0046] Beneficial effects: The electrode structure printing method for the back contact battery provided in this disclosure first prints a non-corrosive sub-gate paste across the entire main gate area, and forms a groove in the middle section. Finally, a corrosive paste is printed simultaneously in the groove and on the surface of the sub-gate area. The resulting main gate electrode has a structure where the middle section is corrosive paste and the sides are non-corrosive paste 90. This structure can effectively collect carriers from the silicon substrate corresponding to the main gate area and also reduces the gold / semi-reinforced composite area. Furthermore, this printing method can reduce the amount of non-corrosive paste 90 used, thus lowering costs.

[0047] In some optional embodiments, the back side of the back contact battery includes a first doped region 11 and a second doped region 12 alternately spaced along a first direction; the first doped region 11 includes a first main gate region 21 and a first sub-gate region 31; the second doped region 12 includes a second main gate region 22 and a second sub-gate region 32; each first main gate region 21 intersects with a plurality of parallel first sub-gate regions 31, and each second main gate region 22 intersects with a plurality of parallel second sub-gate regions 32; The first sub-gate region 31 and the second sub-gate region 32 are arranged alternately along the second direction and both extend along the first direction; the first main gate region 21 and the second main gate region 22 are arranged alternately along the first direction and both extend along the second direction; the first direction is perpendicular to the second direction.

[0048] In some alternative embodiments, after the annealing and sintering process, an electrode structure is formed on the back side of the back contact cell. The electrode structure includes a main gate electrode and a sub-gate electrode. The main gate electrode includes a first main gate electrode and a second main gate electrode located on the surfaces of the first doped region 11 and the second doped region 12, respectively. The sub-gate electrode includes a first sub-gate electrode and a second sub-gate electrode located on the surfaces of the first doped region 11 and the second doped region 12, respectively.

[0049] In some alternative embodiments, after the annealing and sintering process, the non-corrosive slurry 90 and the corrosive slurry in the first main gate region 21 together form the first main gate electrode; the non-corrosive slurry 90 and the corrosive slurry in the second main gate region 22 together form the second main gate electrode; the corrosive slurry in the first sub-gate region 31 forms the first sub-gate electrode; and the corrosive slurry in the second sub-gate region 32 forms the second sub-gate electrode.

[0050] In some alternative implementations, each first main gate electrode intersects with a plurality of parallel first sub-gate electrodes, and each second main gate electrode intersects with a plurality of parallel second sub-gate electrodes; The first sub-gate electrode and the second sub-gate electrode are arranged alternately along the second direction and both extend along the first direction; the first main gate electrode and the second main gate electrode are arranged alternately along the first direction and both extend along the second direction; the first direction is perpendicular to the second direction.

[0051] In some alternative implementations, such as Figure 3 As shown, in Example 1, the steps of printing a corrosive paste on the surface of the sub-gate region and the surface of the main gate region, and printing a non-corrosive paste 90 on the surface of the main gate region, include the following steps S11 to S13.

[0052] S11, simultaneously print the first corrosive paste 81 in the first main grid region 21 and the first secondary grid region 31, such as Figure 4A and Figure 4B As shown.

[0053] In practice, the first corrosive slurry 81 covers the entire first sub-grid region 31 and the middle portion of the first main grid region 21.

[0054] S12, simultaneously print the second corrosive paste 82 in the second main grid region 22 and the second auxiliary grid region 32, such as Figure 4A and Figure 4B As shown.

[0055] In practice, the second corrosive slurry 82 covers the entire second auxiliary grid region 32 and the middle portion of the second main grid region 22.

[0056] S13. Non-corrosive paste 90 is superimposed and printed in the first main grid region 21 and the second main grid region 22. The non-corrosive paste 90 covers the surface and sides of the first corrosive paste 81 and the second corrosive paste 82, such as... Figure 5A and Figure 5B As shown.

[0057] In specific implementation, within the first main grid region 21, the non-corrosive slurry 90 covers the surface and sides of the first corrosive slurry 81 and covers the entire first main grid region 21; within the second main grid region 22, the non-corrosive slurry 90 covers the surface and sides of the second corrosive slurry 82 and covers the entire second main grid region 22.

[0058] Beneficial effects: The electrode structure printing method of the back contact battery provided in this disclosure firstly prints a first etchable paste 81 simultaneously in the first main gate region 21 and the first sub-gate region 31, and secondly prints a second etchable paste 82 simultaneously in the second main gate region 22 and the second sub-gate region 32. Finally, a non-etchable paste 90 is superimposed and printed in the first main gate region 21 and the second main gate region 22. The non-etchable paste 90 covers the surface and side of the first etchable paste 81 and the second etchable paste 82, forming a "pagoda" structure for the first main gate electrode and the second main gate electrode, with an uneven top morphology, which is beneficial to the absorption of incident light and improves the light utilization rate of the back contact battery. At the same time, the non-etchable paste 90 in the first main gate electrode and the second main gate electrode covers the etchable paste, which can fully collect the carriers of the silicon substrate corresponding to the main gate region and reduce the gold / semi-composite area.

[0059] In some alternative implementations, such as Figure 6 As shown, in Example 2, the steps of printing a corrosive paste on the surface of the sub-gate region and the surface of the main gate region, and printing a non-corrosive paste 90 on the surface of the main gate region, include the following steps S21 to S24.

[0060] S21. Simultaneously print non-corrosive paste 90 on the first main grid area 21 and the second main grid area 22 on the back contact of the battery. Figure 7A and Figure 7B As shown.

[0061] S22, Grooves 50 are formed on the surfaces of the non-corrosive slurry 90 in both the first main grid region 21 and the second main grid region 22; the grooves 50 penetrate the non-corrosive slurry 90 and expose the bottom of the first main grid region 21 or the second main grid region 22, such as Figure 8 As shown.

[0062] S23. Simultaneously print the first corrosive paste 81 in the groove 50 corresponding to the first main grid region 21 and on the surface of the first secondary grid region 31, such as... Figure 9A and Figure 9B As shown.

[0063] S24. Simultaneously print a second corrosive paste 82 in the groove 50 corresponding to the second main grid region 22 and on the surface of the second auxiliary grid region 32, such as... Figure 9A and Figure 9B As shown.

[0064] Beneficial Effects: The electrode structure printing method for the back contact battery provided in this disclosure firstly prints a non-corrosive paste 90 simultaneously on the first main gate region 21 and the second main gate region 22 on the back side of the back contact battery. Secondly, grooves are formed on the surfaces of the non-corrosive paste 90 in both the first and second main gate regions 21 and 22. The grooves penetrate the non-corrosive paste 90 and expose the bottom of the first main gate region 21 or the second main gate region 22. Finally, a first corrosive paste 81 is simultaneously printed in the groove corresponding to the first main gate region 21 and on the surface of the first sub-gate region 31; and a second corrosive paste 82 is simultaneously printed in the groove corresponding to the second main gate region 22 and on the surface of the second sub-gate region 32. The formed first and second main gate electrodes both have a structure with corrosive paste in the middle and non-corrosive paste 90 on the sides, which can fully collect carriers on the silicon substrate corresponding to the main gate region and reduce the gold / semi-composite area. At the same time, this printing method can reduce the amount of non-corrosive paste 90 used, thus reducing costs.

[0065] In some alternative embodiments, the step of forming the electrode structure after annealing and sintering includes: After annealing the slurry in the first main gate region 21 and the first sub-gate region 31, the first main gate electrode and the first sub-gate electrode are formed respectively. After annealing the slurry of the second main gate region 22 and the second sub-gate region 32, a second main gate electrode and a second sub-gate electrode are formed respectively; the first main gate electrode and the second main gate electrode are both main gate electrodes; the first sub-gate electrode and the second sub-gate electrode are both sub-gate electrodes.

[0066] In some optional embodiments, the first doped region 11 is a P-type doped region, and the width of the first sub-gate electrode is 5~50 μm; The first corrosive slurry 81 includes nano silver powder, glass powder and solvent; the glass powder contains B2O3, Na2O and SiO2, wherein the content of B2O3 is <30%; the particle size of the glass powder is >2 μm; the solvent includes diethylene glycol butyl ether or polyacrylate; the annealing and sintering temperature of the first corrosive slurry 81 is 700~800℃. The second doped region 12 is an N-type doped region, and the width of the second sub-gate electrode is 5~50 μm; The second corrosive slurry 82 includes nano silver powder, glass powder, and solvent; the glass powder contains PbO, Bi2O3, and TeO2, wherein the content of PbO is <60 wt% and the particle size of the glass powder is >2 μm; the solvent is terpineol or methyl formate; the annealing and sintering temperature of the second corrosive slurry 82 is 700~800℃.

[0067] Specifically, the linewidth of the second sub-gate electrode located in the N-type doped region is 5~30 μm. Compared to the non-corrosive paste 90 of the main gate, the paste at this location needs to have a certain degree of corrosivity because it needs to form an ohmic contact with the silicon at the bottom during sintering. The specific process is as follows: during high-temperature sintering, the glass powder melts and burns through the surface AlO. x and SiN x The dielectric film, while the silver particles in the slurry melt at high temperature, and during the cooling process, the silver recrystallizes and forms a silver-silicon alloy ohmic contact with silicon.

[0068] The linewidth of the first sub-gate electrode located in the P-type doped region is 5~30μm; it also needs to form an ohmic contact with the silicon sintered at the bottom, therefore a highly corrosive paste is selected for printing. Since the surface paste contact characteristics of the n-region are different from those of the p-region, the properties and composition of the corresponding p-region surface sub-gate corrosive paste are also different.

[0069] Beneficial Effects: The electrode structure printing method for the back contact battery provided in this disclosure includes a first etchant 81 for the first sub-gate electrode located in the P-type doped region, comprising nano-silver powder, glass powder, and a solvent; the glass powder contains B2O3, Na2O, and SiO2, wherein the content of B2O3 is <30%; the particle size of the glass powder is >2 μm; the solvent includes diethylene glycol butyl ether or polyacrylate; this etchant can effectively penetrate the passivation film to form an ohmic contact with the P-type doped region, reducing the contact resistance of the first sub-gate electrode. The second etchant 82 for the second sub-gate electrode located in the N-type doped region comprises nano-silver powder, glass powder, and a solvent; the glass powder contains PbO, Bi2O3, and TeO2, wherein the content of PbO is <60 wt%, and the particle size of the glass powder is >2 μm; the solvent is terpineol or methyl formate; this etchant can effectively etch the bottom passivation film and form an ohmic contact with the N-type doped region, reducing the contact resistance of the second sub-gate electrode.

[0070] In some alternative embodiments, the resistivity of the corrosive slurry in contact with silicon is less than 10 mΩ·cm. 2 ; The resistivity of the non-corrosive slurry 90 in contact with silicon is greater than or equal to 10 mΩ / cm. 2 .

[0071] In practical implementation, the resistivity of the non-corrosive slurry 90 in contact with silicon is greater than or equal to 10 mΩ / cm. 2 In practice, "90% non-corrosive slurry" means that the corrosivity is so low that it can be ignored.

[0072] Beneficial effects: The electrode structure printing method for the back contact battery provided in this disclosure has a resistivity of less than 10 mΩ·cm in contact between the corrosive paste and silicon. 2 This ensures that the main and secondary gate electrodes formed after annealing and sintering of the corrosive slurry can fully collect charge carriers from all regions of the silicon substrate, improving carrier utilization and collection efficiency. The resistivity of the non-corrosive slurry in contact with silicon is greater than or equal to 10 mΩ·cm. 2 This can reduce the gold / semi-composite area in the main grid region and simultaneously reduce the line resistance of the grid lines, thereby reducing the resistive loss of charge carriers in the grid lines and further improving the charge carrier collection performance, thus improving the electrical performance of the battery.

[0073] In some optional embodiments, the non-corrosive slurry 90 includes aluminum-free or low-aluminum silver powder, a resin binder, and a solvent; wherein the low-aluminum silver powder has an aluminum content ≤0.5 wt%; the resin binder is a dispersible latex powder or a modified resin; and the solvent is disodium ethylenediaminetetraacetate or stearic acid.

[0074] Beneficial effects: The printing method for the electrode structure of the back contact battery provided in this disclosure uses a non-corrosive paste 90 for printing the main grid area, which includes aluminum-free or low-aluminum-doped silver powder, a resin binder, and a solvent; wherein the aluminum content of the low-aluminum-doped silver powder is ≤0.5 wt%; the resin binder is a dispersible latex powder or a modified resin; and the solvent is disodium ethylenediaminetetraacetate or stearic acid; this ensures a reliable connection between the main grid electrode and the sub-grid electrode and external wires; at the same time, using the non-corrosive paste 90 can reduce the risk of material degradation of the main grid electrode during long-term use, improve durability, and thus improve the reliability and lifespan of the back contact battery electrode structure.

[0075] In some alternative implementations, the corrosive slurry includes silver; Non-corrosive slurry 90 includes silver-plated copper, copper, or nickel.

[0076] In practice, non-corrosive slurries include lower-cost materials such as silver-plated copper, copper, or nickel, which can reduce costs. In addition, non-corrosive slurries 90 also include solvents, binders, and other components; corrosive slurries also include glass powder, solvents, and other components.

[0077] Beneficial effects: The printing method for the electrode structure of the back contact battery provided in this disclosure uses a corrosive paste including silver paste and a non-corrosive paste 90 including silver-coated copper, copper or nickel, which can effectively reduce costs while ensuring electrode contact performance.

[0078] In some alternative implementations, the step of forming the electrode structure after annealing and sintering includes: For corrosive slurries, annealing and sintering are performed at 700~800℃; For non-corrosive slurry 90, anneal and dry at 150~300℃.

[0079] In practice, corrosive pastes need to be sintered at higher temperatures to form ohmic contacts, while non-corrosive pastes only need to be dried to remove organic solvents. Therefore, after printing non-corrosive pastes, only a lower temperature (150~300℃) is required for annealing and drying.

[0080] Beneficial effects: The electrode structure printing method for the back contact battery provided in this disclosure, which involves annealing and drying the non-corrosive paste 90 at 150~300℃, can reduce the difficulty and cost of the process and improve the efficiency and reliability of the back contact battery.

[0081] In some alternative embodiments, the step of annealing and sintering the corrosive paste at 700-800°C is performed after the step of printing the corrosive paste; The step of annealing and drying the non-corrosive paste 90 at 150~300℃ is placed after the step of printing the corrosive paste.

[0082] In some alternative implementations, such as Figure 10 As shown, the back of the back contact battery is also provided with multiple PAD dot areas 60 covering part of the main grid area. The multiple PAD dot areas 60 are evenly distributed along the length direction of each main grid area; the width of the PAD dot area 60 is greater than the width of the main grid area. A corrosive paste is printed on the surfaces of the sub-gate region, the main gate region, and the PAD dot region 60, and a non-corrosive paste 90 is printed on the surfaces of the main gate region and the PAD dot region 60; wherein the non-corrosive paste 90 on the surface of the main gate region is at least located on the side of the corrosive paste; the non-corrosive paste 90 on the surface of the PAD dot region 60 is at least located on the side of the corrosive paste. In the step of forming the electrode structure after annealing and sintering, the electrode structure also includes multiple PAD electrodes disposed in the main gate region.

[0083] In related technologies, the PAD dot area is similar to the main grid area, and its surface is generally only printed with non-corrosive paste.

[0084] Beneficial effects: The electrode structure printing method of the back contact battery provided in this disclosure, by using the same printing method as the main grid area in the PAD point region 60, ensures that the non-corrosive paste 90 on the surface of the PAD point region 60 is at least located on the side of the corrosive paste, and forms the PAD electrode after annealing and sintering, the highly corrosive paste in the PAD point region 60 can melt and pass through the passivation film to form an ohmic structure with the silicon substrate at the bottom, thereby fully collecting the charge carriers of the silicon substrate at the bottom of the PAD point region 60, improving the utilization rate and collection efficiency of the charge carriers, and thus improving the electrical performance of the battery.

[0085] In some alternative implementations, the printing method of the PAD dot area 60 is similar to that of... Figure 3 The printing method and steps for the main grid area are the same. Step S11 further includes: simultaneously printing a first corrosive paste 81 on the surface of the PAD dot area 60 corresponding to the first main grid area 21, such as... Figure 11A As shown. Step S12 further includes: simultaneously printing a second corrosive paste 82 on the surface of the PAD dot area 60 corresponding to the second main gate region 22. Step S14 further includes: simultaneously printing a non-corrosive paste 90 on the surface of the PAD dot area 60 corresponding to the first main gate region 21 and the surface of the PAD dot area 60 corresponding to the second main gate region 22, as shown. Figure 11B As shown.

[0086] In some alternative implementations, the printing method of the PAD dot area 60 is similar to that of... Figure 6 The printing method and steps for the main grid area are the same.

[0087] In some alternative implementations, the four corners of the top view structure of the back contact battery are chamfered. The main gate area near the chamfered structure also includes a corner extension area 70; In the step of forming the electrode structure after annealing and sintering, the main gate electrode also includes a main gate extension electrode located in the corner extension region 70; the main gate extension electrode is disposed opposite to the outermost sub-gate electrode and does not contact it.

[0088] In related technologies, such as Figure 1A As shown, because the sub-gate on the back of the back-contact battery is designed with an interdigitated shape and the structure of each part is generally symmetrical, meaning the number of sub-gates in the P-type doped region is the same as the number of sub-gates in the N-type doped region, and the first and second sub-gate electrodes are arranged alternately, a blank area 3 (i.e., an area without main or sub-gate printing) will inevitably appear near the chamfered structure, corresponding to the outermost first / second sub-gate electrode. However, conventional main gate electrode settings only consider connecting multiple sub-gate electrodes, and the non-corrosive paste selected for conventional main gate electrodes cannot collect carriers in the main gate region. Therefore, paste is not printed in the blank area, resulting in the inability to collect carriers in the silicon substrate corresponding to the blank area near the chamfered structure.

[0089] Beneficial effects: The electrode structure printing method of the back contact battery provided in this disclosure forms a main grid extension electrode in the corner extension region 70 near the chamfered structure. The non-corrosive paste 90 in the main grid extension electrode is located at least on the side of the corrosive paste. This method can effectively collect the charge carriers in the silicon substrate corresponding to the blank area near the chamfered structure, improve the utilization rate and collection efficiency of the charge carriers, and thus improve the electrical performance of the battery.

[0090] In some alternative embodiments, a corrosive paste is first printed on the corner extension area 70 of the middle width, and then a non-corrosive paste 90 is overlaid on the surface of the corner extension area 70, with the non-corrosive paste 90 covering the surface and sides of the corrosive paste.

[0091] In some alternative embodiments, a non-corrosive paste 90 is first printed in the corner extension area 70, and then a groove is formed on the surface of the non-corrosive paste 90; the groove penetrates the non-corrosive paste 90 and exposes the bottom corner extension area 70; finally, a corrosive paste is printed in the groove.

[0092] In some examples, such as Figure 4A and Figure 4B As shown, firstly, a first corrosive paste 81 is printed in the corner extension area 70 corresponding to the first main grid area 21, and second corrosive paste 82 is printed in the corner extension area 70 corresponding to the second main grid area 22. Figure 5A and Figure 5BAs shown, a first corrosive paste 81 and a second corrosive paste 82 are then overlaid and printed in the corner extension area 70 to cover a non-corrosive paste 90; the non-corrosive paste 90 covers the surface and sides of the first corrosive paste 81 or the second corrosive paste 82.

[0093] In other examples, firstly, such as Figure 7A and Figure 7B As shown, a non-corrosive paste 90 is printed in the corner extension area 70; secondly, as... Figure 8 As shown, a groove located at the middle portion width is formed on the surface of the non-corrosive slurry 90 in the corner extension region 70; finally, as... Figure 9A and Figure 9B As shown, a first corrosive paste 81 is printed in the groove corresponding to the first main gate region 21, and a second corrosive paste 82 is printed in the groove corresponding to the second main gate region 22; and a main gate extension electrode located in the corner extension region 70 is formed after the annealing and sintering process.

[0094] In the description of this specification, the references to terms such as "this embodiment," "an embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0095] The above description does not provide detailed explanations of the technical aspects of each layer's patterning, etching, etc. However, those skilled in the art should understand that various technical means can be used to form layers and regions of the desired shape. Furthermore, to form the same structure, those skilled in the art can also design methods that are not entirely identical to those described above. Additionally, although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination.

[0096] The above description is merely a preferred embodiment and the technical principles employed in this disclosure. Those skilled in the art will understand that this disclosure is not limited to the specific embodiments described above, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of this disclosure. Therefore, although this disclosure has been described in detail through the above embodiments, it is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of this disclosure, and the scope of protection of this disclosure is determined by the scope of the appended claims.

Claims

1. A method for printing the electrode structure of a back-contact battery, characterized in that, include: A back contact battery is provided, the back contact battery including a front side and a back side disposed opposite to each other; The back of the back contact battery is provided with a main grid area and a sub-grid area; A corrosive paste is printed on the surface of the sub-gate region and the surface of the main gate region, and a non-corrosive paste is printed on the surface of the main gate region; wherein the non-corrosive paste on the surface of the main gate region is at least located on the side of the corrosive paste; After annealing and sintering, an electrode structure is formed, which includes a main gate electrode located in the main gate region and a sub-gate electrode located in the sub-gate region.

2. The method for printing the electrode structure of the back contact battery according to claim 1, characterized in that, The steps of printing an etchant on the surface of the sub-gate region and the surface of the main gate region, and printing a non-etchant on the surface of the main gate region, include: Etching paste is simultaneously printed in the main grid area and the sub-grid area on the back of the battery. A non-corrosive paste is superimposed and printed on the surface of the main grid area, the non-corrosive paste covering the surface and sides of the corrosive paste.

3. The method for printing the electrode structure of the back contact battery according to claim 1, characterized in that, The steps of printing an etchant on the surface of the sub-gate region and the surface of the main gate region, and printing a non-etchant on the surface of the main gate region, include: A non-corrosive paste is printed in the main grid area on the back of the battery. A groove is formed on the surface of the non-corrosive slurry; the groove penetrates the non-corrosive slurry and exposes the bottom main grid area; A corrosive paste is simultaneously printed within the groove and on the surface of the sub-gate region.

4. The method for printing the electrode structure of the back contact battery according to claim 1, characterized in that, The back side of the back contact battery includes a first doped region and a second doped region alternately spaced along a first direction; the first doped region includes a first main gate region and a first sub-gate region; the second doped region includes a second main gate region and a second sub-gate region; each first main gate region intersects with a plurality of parallel first sub-gate regions, and each second main gate region intersects with a plurality of parallel second sub-gate regions. The first sub-gate region and the second sub-gate region are arranged alternately along the second direction and both extend along the first direction; the first main gate region and the second main gate region are arranged alternately along the first direction and both extend along the second direction; the first direction is perpendicular to the second direction.

5. The method for printing the electrode structure of the back contact battery according to claim 4, characterized in that, The steps of printing an etchant on the surface of the sub-gate region and the surface of the main gate region, and printing a non-etchant on the surface of the main gate region, include: The first corrosive paste is printed simultaneously in the first main grid region and the first sub-grid region; A second corrosive paste is simultaneously printed in the second main grid region and the second sub-grid region; Non-corrosive paste is superimposed and printed in the first main grid area and the second main grid area, the non-corrosive paste covering the surface and side of the first corrosive paste and the second corrosive paste.

6. The method for printing the electrode structure of the back contact battery according to claim 4, characterized in that, The steps of printing an etchant on the surface of the sub-gate region and the surface of the main gate region, and printing a non-etchant on the surface of the main gate region, include: Non-corrosive paste is simultaneously printed in the first and second main grid areas on the back of the battery. Grooves are formed on the surface of the non-corrosive slurry in both the first and second main grid regions; the grooves penetrate the non-corrosive slurry and expose the bottom of the first or second main grid region; A first corrosive paste is simultaneously printed in the groove corresponding to the first main gate area and on the surface of the first secondary gate area; A second corrosive paste is simultaneously printed in the groove corresponding to the second main gate area and on the surface of the second sub-gate area.

7. The method for printing the electrode structure of the back contact battery according to claim 5 or 6, characterized in that, The step of forming the electrode structure after annealing and sintering includes: After annealing the slurry in the first main gate region and the first sub-gate region, the first main gate electrode and the first sub-gate electrode are formed respectively. After annealing the slurry in the second main gate region and the second sub-gate region, a second main gate electrode and a second sub-gate electrode are formed respectively; both the first main gate electrode and the second main gate electrode belong to the main gate electrode; both the first sub-gate electrode and the second sub-gate electrode belong to the sub-gate electrode.

8. The method for printing the electrode structure of the back contact battery according to claim 1, characterized in that, The resistivity of the corrosive slurry in contact with silicon is less than 10 mΩ / cm. 2 ; The resistivity of the non-corrosive slurry in contact with silicon is greater than or equal to 10 mΩ / cm. 2 .

9. The method for printing the electrode structure of the back contact battery according to claim 1, characterized in that, The back of the back contact battery is also provided with multiple PAD dot areas covering part of the main grid area, and the multiple PAD dot areas are evenly distributed along the length direction of each main grid area; the width of the PAD dot area is greater than the width of the main grid area; A corrosive paste is printed on the surfaces of the sub-gate region, the main gate region, and the PAD dot region, and a non-corrosive paste is printed on the surfaces of the main gate region and the PAD dot region; wherein the non-corrosive paste on the surface of the main gate region is at least located on the side of the corrosive paste; the non-corrosive paste on the surface of the PAD dot region is at least located on the side of the corrosive paste. In the step of forming the electrode structure after annealing and sintering, the electrode structure also includes a plurality of PAD electrodes disposed in the main gate region.

10. The method for printing the electrode structure of the back contact battery according to claim 1, characterized in that, The four corners of the back contact battery's top view structure are chamfered. The main gate area near the chamfered structure also includes a corner extension area; In the step of forming the electrode structure after annealing and sintering, the main gate electrode also includes a main gate extension electrode located in the corner region; the main gate extension electrode is disposed opposite to the outermost sub-gate electrode and does not contact it.

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