Preparation method of photovoltaic cell metal grid line and photovoltaic cell

Abstract

The invention discloses a photovoltaic cell metal grid line preparation method and a photovoltaic cell, and the method comprises the following steps: forming a seed layer on an area where a metal grid line is to be formed on one surface of a cell substrate, the coverage area of the seed layer comprising and being larger than the area where the metal grid line is to be formed, the seed layer incompletely covers one surface of the cell substrate; and forming a metal gate line on the seed layer, wherein the metal gate line incompletely covers the seed layer. According to the method, the area of the damaged area on the cell substrate is reduced, and the efficiency damage degree of the photovoltaic cell is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaic, in particular to a preparation method of metal grid line of photovoltaic cell and photovoltaic cell. BACKGROUND

[0002] When the photovoltaic cell adopts the electroplating process to prepare the metal grid line, in order to improve the adhesion of the metal grid line on the TCO film layer, a seed layer is prepared on the TCO (Transparent Conductive Oxide) film layer first, and then the metal grid line is formed on the seed layer. The method for preparing the seed layer (for example, copper seed layer) generally adopts the PVD process, which will cause damage to the TCO film layer and affect the efficiency of the photovoltaic cell. Therefore, it is necessary to reduce the damage to the TCO film layer in the process of depositing the metal seed layer by the PVD process.

[0003] For example, a mask plate made of plastic or resin material can be used to prepare a local seed layer. Since the high molecular thin film material is not resistant to high temperature, it will be deformed in the PVD deposition process, affecting the pattern precision. SUMMARY

[0004] The purpose of the present application is to provide a preparation method of metal grid line of photovoltaic cell to solve one of the technical problems mentioned in the background.

[0005] To achieve the above purpose, the technical solutions provided in the embodiments of the present application are as follows.

[0006] In a first aspect, the embodiments of the present application provide a preparation method of metal grid line of photovoltaic cell, comprising: forming a seed layer on an area on one side of a cell piece substrate where the metal grid line is to be formed, the coverage area of the seed layer containing and being larger than the area where the metal grid line is to be formed, and the seed layer not completely covering the one side of the cell piece substrate.

[0007] Forming a metal grid line on the seed layer, the metal grid line not completely covering the seed layer.

[0008] In some embodiments, according to the shape of the metal grid line to be formed, a seed layer with a similar shape is formed on the area on one side of the cell piece substrate where the metal grid line is to be formed.

[0009] In some embodiments, the method for preparing the metal grid lines of the photovoltaic cell comprises: forming a patterned first mask layer on one side of the cell substrate; using physical vapor deposition, making the target material pass through the patterned area of the first mask layer to deposit the target material on one side of the cell substrate to form the seed layer; removing the first mask layer; forming a patterned second mask layer on one side of the cell substrate; electroplating metal on the patterned area of the second mask layer to form the metal grid lines on the seed layer; removing the second mask layer; etching away the excess seed layer.

[0010] In some embodiments, the patterned first mask layer refers to the slits on the first mask layer with the shape of the seed layer to be formed; the width of the slits is 1.5-50 times the width of the metal grid lines to be formed.

[0011] In some embodiments, the method for preparing the metal grid lines of the photovoltaic cell comprises: pre-manufacturing a patterned high-temperature-resistant mask according to the shape of the seed layer to be formed; placing the high-temperature-resistant mask on one side of the cell substrate; using physical vapor deposition, making the target material pass through the patterned area of the high-temperature-resistant mask to deposit the target material on one side of the cell substrate to form the seed layer; removing the high-temperature-resistant mask; forming a patterned second mask layer on one side of the cell substrate; electroplating metal on the patterned area of the second mask layer to form the metal grid lines on the seed layer; removing the patterned second mask layer; etching away the excess seed layer.

[0012] In some embodiments, the patterned high-temperature-resistant mask refers to the slits on the high-temperature-resistant mask with the shape of the seed layer to be formed; the width of the slits is 1.5-50 times the width of the metal grid lines to be formed.

[0013] In some embodiments, the high-temperature-resistant mask is a first mask, and the first mask cooperates with a carrier to form the seed layer on one side of the cell substrate.

[0014] The carrier comprises a bearing part for bearing the cell substrate, and the bearing part is a groove on the carrier, the shape of the groove is the same as or similar to the shape of the cell substrate, the first mask comprises a first patterned part, and the first patterned part is provided with a first patterned through hole; in use, the first patterned part extends into the groove to cooperate with the groove, the outer contour shape of the first mask is the same as or similar to the shape of the groove, so that the outer peripheral sidewall of the first mask can abut against the inner wall of the groove.

[0015] In some embodiments, the first mask plate further comprises a first sidewall extending upward from the edge of the first patterned portion, the first sidewall abutting the inner wall of the groove, and an upper end of the first sidewall being connected with an outwardly extending overhang; in use, the overhang is lapped on the edge of the groove to limit the depth of the first patterned portion into the groove.

[0016] In some embodiments, the outer wall of the first sidewall is at least partially a first inclined surface, the inner wall of the groove is at least partially a second inclined surface, and the first inclined surface and the second inclined surface cooperate to allow the first mask plate to be engaged with the groove.

[0017] In some embodiments, the first patterned portion is provided with a flexible material layer on the side facing the substrate of the battery piece, and / or the carrying portion of the carrier is provided with a flexible material layer.

[0018] In some embodiments, the high-temperature-resistant mask plate further comprises a second mask plate, the second mask plate comprising a second patterned portion, the second patterned portion being provided with a second patterned through hole, and the carrying portion of the carrier being provided with a penetrating hole.

[0019] In use, the second patterned portion of the second mask plate abuts the lower surface of the carrying portion, so that the second patterned through hole is aligned with the penetrating hole to form a seed layer on the other side of the substrate of the battery piece.

[0020] In some embodiments, the seed layer comprises a plurality of strip structures arranged at intervals on one side of the substrate of the battery piece, and the metal grid lines are formed on each of the strip structures.

[0021] The width of the strip structure is D1, and the width of the metal grid line is D2, and the width D1 of the strip structure is greater than the width D2 of the metal grid line.

[0022] In some embodiments, the seed layer comprises a plurality of strip structures arranged at intervals on one side of the substrate of the battery piece, and the metal grid lines are formed on each of the strip structures.

[0023] The width of the strip structure is D1, the spacing between adjacent two strip structures is D3, and the ratio between the spacing D3 between the strip structures and the width D1 of the strip structure is 1-200.

[0024] In some embodiments, the method for preparing the metal grid lines of the photovoltaic cell further comprises: forming a seed layer on the region of the other side of the substrate of the battery piece where the metal grid lines are to be formed, the coverage area of the seed layer containing and being larger than the region where the metal grid lines are to be formed, and the seed layer not completely covering the other side of the substrate of the battery piece.

[0025] forming a metal grid line on the seed layer, the metal grid line not completely covering the seed layer;

[0026] The one side of the cell substrate and the other side of the cell substrate are two opposite sides of the cell substrate.

[0027] In a second aspect, the embodiments of the present application also provide a photovoltaic cell prepared by the above method.

[0028] By using the above technical solution, the embodiments of the present application have the following advantages compared with the prior art: a seed layer is formed on the area of the one side of the cell substrate where the metal grid line is to be formed, the covering area of the seed layer contains and is larger than the area where the metal grid line is to be formed, and the seed layer does not completely cover the one side of the cell substrate; the area of the cell substrate not covered by the seed layer can be avoided from being damaged, the area of the damaged area on the cell substrate is reduced, and the degree of damage to the efficiency of the photovoltaic cell is reduced.

[0029] The covering area of the seed layer contains and is larger than the area where the metal grid line is to be formed, the metal grid line does not need to be strictly aligned with the edge of the seed layer, the additional equipment and control cost caused thereby is avoided, in addition, the metal grid line and the seed layer are not easy to be misaligned, which is beneficial to maintaining or improving the efficiency of the photovoltaic cell. Furthermore, the deformation of the seed layer is controlled within a certain range, the metal grid line is not formed with its own edge referring to the edge of the seed layer, and therefore the shape of the metal grid line is not affected. BRIEF DESCRIPTION OF DRAWINGS

[0030] FIG. 1 is a flow chart of the preparation of the metal grid line of the photovoltaic cell in the prior art; Figure 1 FIG. 1 is a flow chart of the preparation of the metal grid line of the photovoltaic cell in the prior art;

[0031] FIG. 2 is a flow chart of the preparation of the metal grid line of the single-sided photovoltaic cell in Example 1; Figure 2 FIG. 2 is a flow chart of the preparation of the metal grid line of the single-sided photovoltaic cell in Example 1;

[0032] FIG. 3 is a flow chart of the preparation of the metal grid line of the double-sided photovoltaic cell in Example 1; Figure 3 FIG. 3 is a flow chart of the preparation of the metal grid line of the double-sided photovoltaic cell in Example 1;

[0033] FIG. 4 is a flow chart of the preparation of the metal grid line of the photovoltaic cell in Example 2; Figure 4 FIG. 4 is a flow chart of the preparation of the metal grid line of the photovoltaic cell in Example 2;

[0034] FIG. 5 is a flow chart of the preparation of the seed layer in Example 3; Figure 5 FIG. 5 is a flow chart of the preparation of the seed layer in Example 3;

[0035] FIG. 6 is a schematic diagram of the size relationship between the metal grid line and the seed layer in the embodiments of the present application; Figure 6 FIG. 6 is a schematic diagram of the size relationship between the metal grid line and the seed layer in the embodiments of the present application;

[0036] FIG. 7 is a schematic diagram of the structure of the single-sided patterned structure in the idle state in Example 3; Figure 7 FIG. 7 is a schematic diagram of the structure of the single-sided patterned structure in the idle state in Example 3;

[0037] FIG. 8 is a schematic diagram of the structure of the double-sided patterned structure in the idle state in Example 3;Figure 8 Structure diagram of the structure in the loaded state of the single-sided patterned structure in Example 3;

[0038] Figure 1 Figure 9 Structure diagram of the first mask in Example 3 containing the flexible material layer;

[0039] Figure 1 Figure 10 Second structure diagram of the single-sided patterned structure in Example 3;

[0040] Figure 1 Figure 11 Structure diagram of the structure in the unloaded state of the double-sided patterned structure in Example 3;

[0041] Figure 1 Figure 12 Structure diagram of the structure in the loaded state of the double-sided patterned structure in Example 3;

[0042] In which, the meaning of the reference signs is as follows:

[0043] Battery piece substrate 1, seed layer 2, metal grid line 3, first mask layer 41, second mask layer 42, high-temperature-resistant mask 43, first mask 51, first patterned via hole 51a, overlap 511, first sidewall 512, first patterned part 513, flexible material layer 514, second mask 52, second patterned via hole 52a, second sidewall 522, second patterned part 523, stage 6, accommodating groove 6a, through hole 6b. DETAILED DESCRIPTION

[0044] The preferred embodiments of the present application will be described in detail below with reference to the drawings, so that the advantages and features of the present application can be more easily understood by those skilled in the art. It should be noted that the description of these embodiments is used to help understand the present application, but does not constitute a limitation of the present application. Example 1 is not just one embodiment, but a collection of some embodiments with similar schemes or features, and the same applies to other embodiments.

[0045] When a photovoltaic cell adopts an electroplating process to prepare a metal grid line, in order to improve the adhesion of the metal grid line on the TCO (Transparent Conductive Oxide) film layer, a seed layer is first prepared on the TCO film layer, and then a metal grid line is formed on the seed layer. The method of preparing the seed layer (for example, a copper seed layer) generally adopts a PVD process, which will cause damage to the TCO film layer and affect the efficiency of the photovoltaic cell. Therefore, it is necessary to reduce the damage to the TCO film layer during the process of depositing the metal seed layer by the PVD process.

[0046] In order to better demonstrate the prior art, please refer to Figure 1The metal grid line preparation process shown in FIGS. 1a-1d uses a PVD process to deposit a seed layer 2 on one side of the cell substrate 1, the seed layer 2 completely covers one side of the cell substrate 1, and even covers a local area on the side edge of the cell substrate 1. The metal grid line 3 is formed by electroplating on the seed layer 2. The excess seed layer 2 is removed, that is, the seed layer 2 outside the area occupied by the metal grid line 3 is removed. The TCO film layer is provided on one side or both sides of the cell substrate 1, and the seed layer 2 is formed outside the area occupied by the metal grid line 3, which will cause damage to the TCO film layer on more areas, affecting the efficiency of the photovoltaic cell.

[0047] To solve the above problems, a mask plate made of plastic or resin material can be used to form a seed layer 2 on a local area on one side of the cell substrate 1, which reduces the coverage area of the seed layer 2 on one side of the cell substrate 1. The area of the cell substrate 1 that is not covered by the seed layer 2 will not be damaged, thus reducing the damage to the TCO film layer. However, the mask plate made of plastic or resin material is not resistant to high temperature. In the PVD deposition process in a high temperature environment, the mask plate made of plastic or resin material will deform, affecting the forming precision of the seed layer 2 and causing the seed layer 2 to deform. Further, the shape of the seed layer 2 can be made the same as the shape of the metal grid line 3 to be formed, avoiding subsequent etching of the excess seed layer 2. However, when forming the metal grid line 3 on the seed layer 2, it is necessary to ensure that the edges of the metal grid line 3 and the seed layer 2 are aligned. However, in the micron scale, it is difficult to align the edges of the metal grid line 3 and the seed layer 2, which is prone to misalignment, affecting the efficiency of the photovoltaic cell.

[0048] To better solve the above technical problems, some preferred embodiments will be described in detail below.

[0049] Embodiment 1

[0050] As Figure 2 A method for preparing a metal grid line of a photovoltaic cell, as shown in FIGS. 2a-2d, includes the following steps: forming a seed layer 2 on an area on one side of the cell substrate 1 where the metal grid line 3 is to be formed. The coverage area of the seed layer 2 includes and is larger than the area where the metal grid line 3 is to be formed, and the seed layer 2 does not completely cover one side of the cell substrate 1. The area of the cell substrate 1 that is not covered by the seed layer 2 can be avoided from being damaged, reducing the area of the damaged area on the cell substrate 1 and reducing the degree of damage to the efficiency of the photovoltaic cell. The seed layer 2 covers the cell substrate 1, and the seed layer 2 will damage the TCO film layer in the cell substrate 1, thereby affecting the short-circuit current Isc of the photovoltaic cell. The larger the coverage area of the seed layer 2, the greater the damage to the TCO film layer in the cell substrate 1, and the smaller the short-circuit current Isc of the photovoltaic cell. Therefore, reducing the coverage area of the seed layer 2 can effectively improve the short-circuit current Isc of the photovoltaic cell.

[0051] Metal grid lines 3 are formed on seed layer 2, but the metal grid lines 3 do not completely cover seed layer 2. That is, the coverage area of ​​seed layer 2 includes and is larger than the area where the metal grid lines 3 are formed. The metal grid lines 3 do not need to be strictly aligned with the edge of seed layer 2, avoiding additional equipment and control costs. Furthermore, the metal grid lines 3 are less likely to misalign with seed layer 2, which helps maintain or improve the efficiency of the photovoltaic cells. Moreover, the deformation of seed layer 2 is controlled within a certain range, and the metal grid lines 3 do not form their own edges with reference to the edge of seed layer 2, thus not affecting the shape of the metal grid lines 3.

[0052] In some embodiments, a seed layer 2 of a similar shape is formed on one side of the solar cell substrate 1 in the area where the metal grid lines 3 are to be formed, based on the shape of the metal grid lines 3 to be formed. That is, the shape of the seed layer 2 is similar to the shape of the metal grid lines 3 to be formed, but their areas are different. For example, if the shape of the metal grid lines 3 to be formed is rectangular, the shape of the seed layer 2 is also rectangular. This allows the formation position of the metal grid lines 3 to be determined based on the edges of the seed layer 2, facilitating the formation of the metal grid lines 3. Furthermore, since the area occupied by the metal grid lines 3 on the seed layer 2 is determined, the area on the seed layer 2 not occupied by the metal grid lines 3 is also determined, facilitating the etching away of the area on the seed layer 2 not occupied by the metal grid lines 3. The shape of the seed layer 2 can be the shape of its orthographic projection onto the solar cell substrate 1. The shape of the metal grid lines 3 to be formed can also be the shape of their orthographic projection onto the solar cell substrate 1.

[0053] In some implementations, such as Figure 3 The method for fabricating the photovoltaic cell metal grid lines shown in Figures 3a to 3d includes the following steps: forming a seed layer 2 on one side of the cell substrate 1 in the area where the metal grid lines 3 are to be formed, wherein the coverage area of ​​the seed layer 2 includes and is larger than the area where the metal grid lines 3 are to be formed, and the seed layer 2 does not completely cover one side of the cell substrate 1; forming a seed layer 2 on the other side of the cell substrate 1 in the area where the metal grid lines 3 are to be formed, wherein the coverage area of ​​the seed layer 2 includes and is larger than the area where the metal grid lines 3 are to be formed, and the seed layer 2 does not completely cover the other side of the cell substrate 1; forming metal grid lines 3 on the seed layer 2, wherein the metal grid lines 3 do not completely cover the seed layer 2; one side and the other side of the cell substrate 1 are two opposite sides of the cell substrate 1. Preferably, according to the shape of the metal grid lines 3 to be formed, a seed layer 2 of a similar shape is formed on the other side of the cell substrate 1 in the area where the metal grid lines 3 are to be formed. Specifically, one side of the cell substrate 1 is the upper surface of the cell substrate 1, and the other side of the cell substrate 1 is the lower surface of the cell substrate 1.

[0054] In some embodiments, the structures formed at each stage of the fabrication process of the photovoltaic cell metal grid lines are referred to as photovoltaic cell intermediates. For example,Figure 2 b. a structure in which a seed layer 2 is formed on one side of a cell substrate 1, Figure 2 c. a structure in which a seed layer 2 and a metal grid line 3 are formed on one side of a cell substrate 1, Figure 3 b. a structure in which a seed layer 2 is formed on both sides of a cell substrate 1, Figure 3 c. a structure in which a seed layer 2 and a metal grid line 3 are formed on both sides of a cell substrate 1, can be referred to as a photovoltaic cell intermediate.

[0055] In Figure 2 c. and Figure 3 c. shown in the photovoltaic cell intermediate, the seed layer 2 includes a plurality of strip structures arranged at intervals on one side of the cell substrate 1, and the metal grid line 3 is formed on each strip structure; in Figure 3 c. shown in the photovoltaic cell intermediate, the seed layer 2 further includes a plurality of strip structures arranged at intervals on the other side of the cell substrate 1, and the metal grid line 3 is formed on each strip structure. As Figure 6 shown, the width of the strip structure is D1, the width of the metal grid line 3 is D2, and the width D1 of the strip structure is greater than the width D2 of the metal grid line 3. Preferably, the ratio between the width D1 of the strip structure and the width D2 of the metal grid line 3 is 1.5-50, so that the area of the seed layer 2 covering the cell substrate 1 is kept within an appropriate range, so as not to excessively damage the TCO film layer due to the area of the seed layer 2 covering the cell substrate 1 being too large, and so as not to be detrimental to the formation of the metal grid line 3 due to the area of the seed layer 2 covering the cell substrate 1 being too small. For example, the ratio between the width D1 of the strip structure and the width D2 of the metal grid line 3 can be 1.5, 2, 3, 5, 8, 10, 15, 20, 25, 30, 35, 40, 45 or 50.

[0056] Preferably, the spacing between two adjacent strip structures is D3, and the ratio between the spacing D3 between the strip structures and the width D1 of the strip structure is 1-200, so that the area of the cell substrate 1 not occupied by the seed layer 2 and the area of the cell substrate 1 occupied by the seed layer 2 are kept at an appropriate ratio, facilitating the formation of the seed layer 2. For example, the ratio between the spacing D3 between the strip structures and the width D1 of the strip structure can be 1, 1.2, 5, 5.1, 10, 15, 20, 30, 50, 80, 100, 150 or 200.

[0057] Example 2

[0058] As Figure 4The method for preparing the metal grid lines of the photovoltaic cells shown in Figs. 4a to 4h comprises the following steps: providing a cell substrate 1; forming a patterned first mask layer 41 on one side of the cell substrate 1; using physical vapor deposition, making the target material pass through the patterned area of the first mask layer 41 to deposit the target material on one side of the cell substrate 1 to form a seed layer 2. Removing the first mask layer 41; forming a patterned second mask layer 42 on one side of the cell substrate 1; electroplating metal on the patterned area of the second mask layer 42 to form metal grid lines 3 on the seed layer 2; removing the second mask layer 42; etching away the excess seed layer 2.

[0059] In the method, the seed layer 2 does not completely cover one side of the cell substrate 1; the area of the cell substrate 1 not covered by the seed layer 2 can be avoided from being damaged, the area of the damaged area of the cell substrate 1 is reduced, and the degree of damage to the efficiency of the photovoltaic cell is reduced.

[0060] In the method, the metal grid lines 3 are formed on the seed layer 2, and the metal grid lines 3 do not completely cover the seed layer 2. That is, the coverage area of the seed layer 2 includes and is larger than the area where the metal grid lines 3 are formed, and the metal grid lines 3 do not need to be strictly aligned with the edges of the seed layer 2, thereby avoiding additional equipment and control costs. In addition, the metal grid lines 3 and the seed layer 2 are not prone to misalignment, which is conducive to maintaining or improving the efficiency of the photovoltaic cell. Furthermore, the deformation of the seed layer 2 is controlled within a certain range, and the metal grid lines 3 are not formed with their own edges referring to the edges of the seed layer 2, so that the shape of the metal grid lines 3 is not affected.

[0061] Preferably, the first mask layer 41 is made of a high-temperature-resistant material that is not prone to deformation at high temperatures. In the PVD deposition process in a high-temperature environment, the first mask layer 41 is used to replace the mask plate made of plastic or resin material, and the first mask layer 41 has less deformation, which can reduce the influence on the forming precision of the seed layer 2 and reduce the deformation rate of the seed layer 2. The existing mask plate made of plastic or resin material has a high cost and thus needs to be repeatedly used. The cumulative deformation during the repeated use process will continuously increase. In the present embodiment, the first mask layer 41 is a production consumable, and the first mask layer 41 formed on each cell substrate 1 is newly prepared and does not have the problem of cumulative deformation, which can improve the forming precision of the seed layer 2. Preferably, the first mask layer 41 is made of a thermosetting or low-cost photopolymerization mask material, and the softening point of the first mask layer 41 is higher than the temperature in the PVD process, so as to ensure that the first mask layer 41 has less deformation in the PVD deposition process. The first mask layer 41 can be formed by using a screen printing or inkjet printing process.

[0062] In some embodiments, the patterned first mask layer 41 refers to a slit on the first mask layer 41 with a shape of the seed layer 2 to be formed; the slit width is 1.5-50 times of the width of the metal grid line 3 to be formed, for example, can be a multiple of the following values: 1.5, 2, 3, 5, 8, 10, 15, 20, 25, 30, 35, 40, 45 or 50.

[0063] In some embodiments, forming the patterned first mask layer 41 on one side of the cell substrate 1 comprises: coating a mask material layer on one side of the cell substrate 1, exposing a preset position on the mask material layer according to a preset pattern, and then developing the exposed mask material layer to obtain the patterned first mask layer 41.

[0064] In some embodiments, the patterned region of the first mask layer 41 refers to a region on the first mask layer 41 from which the mask is removed after exposure and development, which is an open region (for example, the slit mentioned above) on the first mask layer 41 that is connected to the surface of the cell substrate 1.

[0065] In some embodiments, the method for removing the first mask layer 41 comprises chemical immersion or physical peeling using a film-removing chemical solution.

[0066] In some embodiments, forming the patterned second mask layer 42 on one side of the cell substrate 1 comprises: coating a mask material layer on one side of the cell substrate 1 (including the region not occupied by the seed layer 2 and the region occupied by the seed layer 2), the thickness of the mask material layer being greater than the thickness of the seed layer 2, exposing a preset position on the mask material layer according to a preset pattern, and then developing the exposed mask material layer to obtain the patterned second mask layer 42. Preferably, the second mask layer 42 is a transparent material layer, and the corners of the seed layer 2 below the second mask layer 42 can be observed through the second mask layer 42, thereby facilitating positioning and forming a mask-removed region on the second mask layer 42.

[0067] In some embodiments, the patterned region of the second mask layer 42 refers to a region on the second mask layer 42 from which the mask is removed after exposure and development, which is an open region on the second mask layer 42 that is connected to the seed layer 2. Electroplating metal on the patterned region of the second mask layer 42 refers to electroplating metal on the mask-removed region, that is, the metal grid line 3 is plated on the surface of the seed layer 2 through the mask-removed region.

[0068] In some embodiments, the method for removing the second mask layer 42 comprises chemical immersion or physical peeling using a film-removing chemical solution.

[0069] In some embodiments, etching away the excess seed layer 2, i.e. removing the seed layer 2 outside the area occupied by the metal grid lines 3, comprises etching away the excess seed layer 2 using an acid solution.

[0070] In some embodiments, the method for preparing the metal grid lines of a photovoltaic cell, especially for preparing the metal grid lines on a double-sided photovoltaic cell, can comprise the following steps: providing a cell substrate 1; forming a patterned first mask layer 41 on both sides of the cell substrate 1; using physical vapor deposition, allowing the target material to pass through the patterned area of the first mask layer 41 to form a seed layer 2 on both sides of the cell substrate 1; removing the first mask layer 41; forming a patterned second mask layer 42 on both sides of the cell substrate 1; electroplating metal on the patterned area of the second mask layer 42 to form metal grid lines 3 on the seed layer 2; removing the second mask layer 42; etching away the excess seed layer 2.

[0071] In some embodiments, the structure formed in each stage of the method for preparing the metal grid lines of a photovoltaic cell is referred to as a photovoltaic cell intermediate, for example, Figure 4 b-4g as shown in Figure 4 In the photovoltaic cell intermediate shown in g, the seed layer 2 comprises a plurality of strip structures arranged at intervals on one side of the cell substrate 1, and the metal grid lines 3 are formed on each strip structure. As shown in Figure 6 The width of the strip structure is D1, and the width of the metal grid line 3 is D2. The width D1 of the strip structure is greater than the width D2 of the metal grid line 3. Preferably, the ratio between the width D1 of the strip structure and the width D2 of the metal grid line 3 is 1.5-50, so that the area of the seed layer 2 covering the cell substrate 1 is kept within an appropriate range, so as to avoid the area of the seed layer 2 covering the cell substrate 1 being too large, which would excessively damage the TCO film layer, or the area of the seed layer 2 covering the cell substrate 1 being too small, which would be unfavorable for the formation of the metal grid lines 3. For example, the ratio between the width D1 of the strip structure and the width D2 of the metal grid line 3 can be 1.5, 2, 3, 5, 8, 10, 15, 20, 25, 30, 35, 40, 45 or 50.

[0072] Preferably, the distance between adjacent two strip structures is D3, and the ratio between the distance D3 between the strip structures and the width D1 of the strip structure is 1-200, so that the area of the seed layer 2 covering the cell substrate 1 and the area of the cell substrate 1 not covered by the seed layer 2 are kept at an appropriate ratio, which facilitates the formation of the seed layer 2. For example, the ratio between the distance D3 between the strip structures and the width D1 of the strip structure can be 1, 1.2, 5, 5.1, 10, 15, 20, 30, 50, 80, 100, 150 or 200.

[0073] The contents not described in detail in the present embodiment can refer to or quote Embodiment 1.

[0074] Embodiment 3

[0075] The method for preparing the metal grid line of the photovoltaic cell in the present embodiment comprises the following steps:

[0076] Preparation of the seed layer 2: providing the cell piece substrate 1; pre-manufacturing a patterned high-temperature-resistant mask plate 43 according to the shape of the seed layer 2 to be formed; setting the high-temperature-resistant mask plate 43 on one side of the cell piece substrate 1; using the physical vapor deposition method to make the target material pass through the patterned area of the high-temperature-resistant mask plate 43 to deposit the target material on one side of the cell piece substrate 1 to form the seed layer 2. The structure of the product at each stage in the preparation process of the seed layer 2 can refer to the structure shown in Figs. 5a-5d. Figure 5 Preferably, when the high-temperature-resistant mask plate 43 is set on one side of the cell piece substrate 1, the high-temperature-resistant mask plate 43 is in abutment or clamped or other detachable way fixedly connected with the carrier plate bearing the cell piece substrate 1, so that the relative position of the high-temperature-resistant mask plate 43 and the cell piece substrate 1 is fixed, thereby ensuring that the position of the seed layer 2 formed on one side of the cell piece substrate 1 is not deviated or deviated slightly.

[0077] Preparation of the metal grid line 3: removing the high-temperature-resistant mask plate 43; forming a patterned second mask layer 42 on one side of the cell piece substrate 1; electroplating metal on the patterned area of the second mask layer 42 to form the metal grid line 3 on the seed layer 2; removing the patterned second mask layer 42; etching away the excess seed layer 2. After removing the high-temperature-resistant mask plate 43, the structure of the product at each stage in the preparation process of the metal grid line 3 can refer to the structure shown in Figs. 4f-4h.

[0078] In the present embodiment, the seed layer 2 does not completely cover one side of the cell piece substrate 1; the area of the cell piece substrate 1 not covered by the seed layer 2 can be avoided from being damaged, thereby reducing the area of the damaged area on the cell piece substrate 1 and reducing the degree of damage to the efficiency of the photovoltaic cell.

[0079] In the present embodiment, the metal grid line 3 is formed on the seed layer 2, and the metal grid line 3 does not completely cover the seed layer 2. That is, the coverage area of the seed layer 2 contains and is larger than the area where the metal grid line 3 is formed, and the metal grid line 3 does not need to be strictly aligned with the edge of the seed layer 2, thereby avoiding the additional equipment and control costs caused thereby, in addition, the metal grid line 3 and the seed layer 2 are not easy to be misaligned, which is conducive to maintaining or improving the efficiency of the photovoltaic cell. Furthermore, the deformation of the seed layer 2 is controlled within a certain range, and the metal grid line 3 is not formed with its own edge by referring to the edge of the seed layer 2, so that the shape of the metal grid line 3 is not affected.

[0080] The high-temperature-resistant mask plate 43 in this embodiment is itself a high-temperature-resistant material and is not prone to deformation at high temperatures. In the PVD deposition process in a high-temperature environment, the high-temperature-resistant mask plate 43 is used to replace the mask plate of plastic or resin material, the high-temperature-resistant mask plate 43 is less deformed, and the influence on the forming precision of the seed layer 2 and the deformation rate of the seed layer 2 can be reduced. Preferably, the material of the high-temperature-resistant mask plate 43 can be a high-temperature-resistant material such as metal or graphite or ceramic, which is not prone to deformation at high temperatures. The metal material includes 316 stainless steel, titanium, or titanium alloy.

[0081] In some embodiments, the patterned high-temperature-resistant mask plate 43 refers to a high-temperature-resistant mask plate 43 having a slit with the shape of the seed layer 2 to be formed on the high-temperature-resistant mask plate 43; the width of the slit is 1.5-50 times the width of the metal grid line 3 to be formed, for example, can be a multiple of the following values: 1.5, 2, 3, 5, 8, 10, 15, 20, 25, 30, 35, 40, 45, or 50.

[0082] In some embodiments, the pre-manufacturing of a patterned high-temperature-resistant mask plate 43 according to the shape of the seed layer 2 to be formed includes: forming a hollow area (for example, the slit described above) on a metal sheet with a size comparable to that of the battery piece substrate 1, the shape of the hollow area is consistent with the shape of the seed layer 2 to be formed on the battery piece substrate 1, and the metal sheet with the hollow area is referred to as a patterned high-temperature-resistant mask plate 43. For example, the seed layer 2 includes a plurality of rectangular block structures arranged at intervals on one side of the battery piece substrate 1, and correspondingly, the hollow area on the metal sheet is a plurality of rectangular hollow holes arranged at intervals.

[0083] In some embodiments, the target material is also deposited on the patterned area of the high-temperature-resistant mask plate 43, which affects the forming precision of the seed layer 2, and therefore the patterned area of the high-temperature-resistant mask plate 43 can be etched regularly to remove the target material deposited on the patterned area of the high-temperature-resistant mask plate 43.

[0084] In some embodiments, the method for preparing the metal grid line of the photovoltaic cell, especially for preparing the metal grid line on the double-sided photovoltaic cell, can include the following steps:

[0085] Preparation of the seed layer 2: providing the battery piece substrate 1; pre-manufacturing two patterned high-temperature-resistant mask plates 43 according to the shape of the seed layer 2 to be formed on the two sides of the battery piece substrate 1; arranging the two high-temperature-resistant mask plates 43 one by one on the two sides of the battery piece substrate 1; and using the physical vapor deposition method to make the target material pass through the patterned area of the high-temperature-resistant mask plate 43 to form the seed layer 2 on the two sides of the battery piece substrate 1.

[0086] Preparation of the metal grid line 3: remove the high-temperature resistant mask plate 43 on both sides of the battery piece substrate 1; form a patterned second mask layer 42 on both sides of the battery piece substrate 1 respectively; electroplate metal on the patterned area of the second mask layer 42 to form the metal grid line 3 on the seed layer 2; remove the patterned second mask layer 42; etch away the excess seed layer 2.

[0087] In the present embodiment, the two sides of the battery piece substrate 1 refer to the two opposite sides of the battery piece substrate 1.

[0088] In some embodiments, the present embodiment provides a photovoltaic cell intermediate formed in the implementation process, which has a structure as shown in Figure 6 The width of the strip block structure is D1, the width of the metal grid line 3 is D2, and the width D1 of the strip block structure is greater than the width D2 of the metal grid line 3. Preferably, the ratio between the width D1 of the strip block structure and the width D2 of the metal grid line 3 is 1.5-50, so that the area of the seed layer 2 covering on the battery piece substrate 1 is kept in a proper range, so as not to damage the TCO film layer too much due to the excessive area of the seed layer 2 covering on the battery piece substrate 1, and so as to facilitate the formation of the metal grid line 3 due to the insufficient area of the seed layer 2 covering on the battery piece substrate 1. For example, the ratio between the width D1 of the strip block structure and the width D2 of the metal grid line 3 can be 1.5, 2, 3, 5, 8, 10, 15, 20, 25, 30, 35, 40, 45 or 50.

[0089] Preferably, the spacing between the two adjacent strip block structures is D3, and the ratio between the spacing D3 between the strip block structures and the width D1 of the strip block structure is 1-200, so that the area of the seed layer 2 covering on the battery piece substrate 1 and the area of the seed layer 2 not covering on the battery piece substrate 1 are kept in a proper ratio, facilitating the formation of the seed layer 2. For example, the ratio between the spacing D3 between the strip block structures and the width D1 of the strip block structure can be 1, 1.2, 5, 5.1, 10, 15, 20, 30, 50, 80, 100, 150 or 200.

[0090] The contents not described in detail in the present embodiment can be referred to or cited from Embodiment 1 and Embodiment 2.

[0091] Embodiment 4

[0092] The present embodiment provides a patterned structure of a battery piece substrate 1, which can be applied to the preparation method of the photovoltaic cell metal grid line in Embodiment 3, to improve the fixing effect on the battery piece substrate 1 and improve the forming precision of the seed layer on the battery piece substrate 1.

[0093] As shown in Figures 7-12As shown, the patterning structure of the battery piece substrate 1 comprises a carrier 6 and a first mask plate 51 cooperating with the carrier 6. The carrier 6 comprises a bearing portion for bearing the battery piece substrate 1. The first mask plate 51 comprises a first patterning portion 513, and the first patterning portion 513 is provided with first patterning through holes 51a. The first patterning portion 513 is a plate structure or the side of the first patterning portion 513 facing the battery piece substrate 1 during use is a plane, and the first patterning through holes 51a penetrate the first patterning portion 513 along the thickness direction of the first patterning portion 513. Preferably, the first patterning through holes 51a are slits in the shape of the seed layer 2 to be formed, and the first patterning through holes 51a are arranged in multiple. During use, the battery piece substrate 1 is placed on the bearing portion of the carrier 6, so that the side of the battery piece substrate 1 requiring the formation of the seed layer faces upward, and the first patterning portion 513 of the first mask plate 51 is arranged on the side of the battery piece substrate 1 requiring the formation of the seed layer (arranged with a gap or abuttingly arranged), so that the first patterning through holes 51a are aligned with the region of the battery piece substrate 1 requiring the formation of the seed layer.

[0094] In some embodiments, as Figures 7-8 As shown, the bearing portion is a groove on the carrier 6, and the shape of the groove is the same as or similar to the shape of the battery piece substrate 1, so as to facilitate the holding of the battery piece substrate 1. The first patterning portion 513 of the first mask plate 51 extends into the groove and cooperates with the groove. The first mask plate 51 can be a plate structure comprising only the first patterning portion 513, and the outer contour shape of the first mask plate 51 is the same as or similar to the shape of the groove, so that the outer peripheral side wall of the first mask plate 51 can abut the inner wall of the groove, so as to reduce the risk of leakage of target material between the first mask plate 51 and the inner wall of the groove, and further reduce the risk of deposition of target material on the unnecessary region of the battery piece substrate 1.

[0095] The first mask plate 51 further comprises a first side wall 512 extending upward from the edge of the first patterning portion 513, and the first side wall 512 abuts the inner wall of the groove. Preferably, the first mask plate 51 is a basin structure, the first side wall 512 is an annular wall of the basin structure, and the first patterning portion 513 is a bottom wall of the basin structure. The annular wall abuts the inner wall of the groove, which can further reduce the risk of leakage of target material between the first mask plate 51 and the inner wall of the groove.

[0096] The upper end of the first sidewall 512 is connected with an outwardly extending overhang 511, where the outwardly extending refers to extending away from the center line direction of the first patterning part 513. The overhang 511 is lapped on the edge of the groove, which can limit the depth of the first patterning part 513 extending into the groove, avoid the first patterning part 513 directly abutting the groove bottom, so that the accommodation groove 6a for accommodating the battery piece substrate 1 can be formed between the first patterning part 513 and the groove bottom. At the same time, the overhang 511 is arranged, which is convenient for the alignment installation of the first mask plate 51 and the groove, and is convenient for the disassembly between the first mask plate 51 and the groove. If the first mask plate 51 is a basin-shaped structure, the overhang 511 is a lip of the basin-shaped structure.

[0097] In the target material deposition process, if there is a gap between the first patterning part 513 and the side of the battery piece substrate 1 which needs to form a seed layer, the area of the seed layer formed will be expanded, that is, the seed layer will be formed on the unnecessary area. The material of the first mask plate 51 is a hard material, such as metal or ceramic or graphite. If the first patterning part 513 abuts or closely contacts the side of the battery piece substrate 1 which needs to form a seed layer, the battery piece substrate 1 will be broken. Therefore, as shown in the figure, a flexible material layer 514 can be arranged on the side of the first patterning part 513 facing the battery piece substrate 1, so as to protect the battery piece substrate 1 in the process of abutting or closely contacting the side of the battery piece substrate 1 which needs to form a seed layer by the first patterning part 513, and reduce the risk of breaking the battery piece substrate 1 in the process of contacting the first patterning part 513. The flexible material layer 514 can also be arranged on the bearing part of the carrier 6 to protect the side of the battery piece substrate 1 contacting the bearing part and reduce the risk of breaking the battery piece substrate 1. Figure 9

[0098] In some embodiments, as shown in the figure, the first mask plate 51 includes the first patterning part 513 and the first sidewall 512 extending upward from the edge of the first patterning part 513, and the outer wall of the first sidewall 512 is at least partially a first inclined surface. The bearing part is a groove on the carrier 6, and the inner wall of the groove is at least partially a second inclined surface. The first inclined surface and the second inclined surface cooperate with each other to make the first mask plate 51 and the groove engage, which is convenient for the alignment installation and disassembly of the first mask plate 51 and the groove. By adjusting the size of the first inclined surface and the second inclined surface, the accommodation groove 6a for accommodating the battery piece substrate 1 can be formed between the first patterning part 513 and the groove bottom. Figure 10 When the seed layer needs to be formed on both sides of the battery piece substrate 1, as shown in the figure, the first mask plate 51 includes the first patterning part 513 and the first sidewall 512 extending upward from the edge of the first patterning part 513, and the outer wall of the first sidewall 512 is at least partially a first inclined surface. The bearing part is a groove on the carrier 6, and the inner wall of the groove is at least partially a second inclined surface. The first inclined surface and the second inclined surface cooperate with each other to make the first mask plate 51 and the groove engage, which is convenient for the alignment installation and disassembly of the first mask plate 51 and the groove. By adjusting the size of the first inclined surface and the second inclined surface, the accommodation groove 6a for accommodating the battery piece substrate 1 can be formed between the first patterning part 513 and the groove bottom.

[0099] Figures 11-12 ​​As shown, the patterning structure of the battery piece substrate 1 comprises the carrier 6, the first mask plate 51 and the second mask plate 52. The first mask plate 51 and the carrying part of the carrier 6 cooperate to facilitate the formation of the seed layer on one side of the battery piece substrate 1. The second mask plate 52 and the carrying part of the carrier 6 cooperate to facilitate the formation of the seed layer on the other side of the battery piece substrate 1. If the battery piece substrate 1 is subjected to PVD treatment in a horizontal state, the one side of the battery piece substrate 1 is the upper surface of the battery piece substrate 1, and the other side of the battery piece substrate 1 is the lower surface of the battery piece substrate 1.

[0100] Specifically, the first mask plate 51 can adopt the structure described above. The carrying part of the carrier 6 is provided with a through hole 6b, the through hole 6b is the same as or similar to the shape of the seed layer 2 to be formed, and the through hole 6b penetrates the carrying part. In use, the target material can pass through the through hole 6b and be deposited on the other side of the battery piece substrate 1.

[0101] More specifically, the second mask plate 52 comprises a second patterning part 523, and the second patterning part 523 is provided with a second patterning through hole 52a. The second patterning part 523 is a plate structure or the side of the second patterning part 523 facing the battery piece substrate 1 in use is a plane, and the second patterning through hole 52a penetrates the second patterning part 523 along the thickness direction of the second patterning part 523. Preferably, the second patterning through hole 52a is a slit in the shape of the seed layer 2 to be formed, and the second patterning through hole 52a is a plurality of through holes arranged at intervals. In use, the battery piece substrate 1 is placed on the carrying part of the carrier 6, so that the upper surface of the battery piece substrate 1 faces upward, the lower surface of the battery piece substrate 1 faces downward, the second patterning part 523 of the second mask plate 52 abuts against the lower surface of the carrying part, and the second patterning through hole 52a is aligned with the through hole 6b to form the seed layer on the lower surface of the battery piece substrate 1. The first mask plate 51 is aligned with the carrier 6 to form the seed layer on the upper surface of the battery piece substrate 1.

[0102] The second mask plate 52 further comprises a second side wall 522 extending upward from the edge of the second patterning part 523, and the second side wall 522 abuts against the peripheral side wall of the carrier 6, so that the second mask plate 52 and the carrier 6 can be clamped and fixed to avoid displacement therebetween. Preferably, the second mask plate 52 is a basin structure, the second side wall 522 is an annular wall of the basin structure, and the second patterning part 523 is a bottom wall of the basin structure. The annular wall abuts against the peripheral side wall of the carrier 6 to reduce the risk of target material leakage between the second mask plate 52 and the peripheral side wall of the carrier 6.

[0103] In some embodiments, the first patterning part 513 and the second patterning part 523 are also deposited with target material, which affects the forming accuracy of the seed layer 2. Therefore, the first patterning part 513 and the second patterning part 523 can be etched periodically to remove the target material deposited thereon.

[0104] In other embodiments, the second mask 52 can be omitted or integrated with the carrier 6, and the seed layer of the desired shape is formed with the aid of the through holes 6b, so that the structure is simplified.

[0105] In addition, the embodiments of the present application also provide a PVD deposition device for preparing a seed layer of a photovoltaic cell, which comprises the aforementioned patterning structure.

[0106] Furthermore, the embodiments of the present application also provide a photovoltaic cell prepared by the method for preparing a metal grid line of a photovoltaic cell in Embodiments 1-3.

[0107] It should be noted that the seed layer 2 comprises a single metal layer, a single metal alloy layer or a multi-layer structure composed of at least two different single layers. For example, the material of the seed layer 2 can be aluminum, copper, tin, cobalt, nickel, silver, tin-lead alloy, tin-silver alloy, copper-nickel alloy, copper-chromium alloy, copper-ruthenium alloy, copper-rhodium alloy, copper-silver alloy, copper-iridium alloy, copper-palladium alloy, copper-platinum alloy, copper-gold alloy and copper-rare earth alloy, copper-nickel-silver alloy and copper-nickel-rare earth metal alloy. The material of the seed layer 2 is preferably copper, copper-nickel alloy, copper-tin alloy, copper-ruthenium alloy and copper-rhodium alloy.

[0108] It should be noted that the metal grid line 3 comprises a single metal layer, a single metal alloy layer or a multi-layer structure composed of at least two different single layers. For example, the material of the metal grid line 3 can be copper, tin, copper-tin alloy or copper-tin laminated structure.

[0109] The above embodiments are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and essence of the present application should be covered within the protection scope of the present application.

Claims

1. A method of fabricating a metal grid line for a photovoltaic cell, the method comprising: The method comprises the following steps: ​ forming a seed layer on the area of the one side of the cell substrate where the metal grid lines are to be formed, the coverage area of the seed layer containing and being larger than the area where the metal grid lines are to be formed, the seed layer not completely covering the one side of the cell substrate; forming the metal grid lines on the seed layer, the metal grid lines not completely covering the seed layer.

2. The method according to claim 1, wherein: forming a seed layer with a similar shape to the metal grid lines to be formed on the area of the one side of the cell substrate where the metal grid lines are to be formed according to the shape of the metal grid lines to be formed.

3. The method of claim 1, wherein the metal grid lines are formed by a process selected from the group consisting of screen printing, inkjet printing, and laser direct writing. The method comprises the following steps: forming a patterned first mask layer on the one side of the cell substrate; using physical vapor deposition method, making the target material pass through the patterned area of the first mask layer to deposit the target material on the one side of the cell substrate to form the seed layer.

4. The method according to claim 3, wherein: the patterned first mask layer refers to the slits on the first mask layer with the shape of the seed layer to be formed; the width of the slits is 1.5-50 times the width of the metal grid lines to be formed.

5. The method of claim 3, wherein the metal grid lines are formed by a screen printing process. The method further comprises the following steps: removing the first mask layer; forming a patterned second mask layer on the one side of the cell substrate; electroplating metal on the patterned area of the second mask layer to form the metal grid lines on the seed layer; removing the second mask layer; etching away the excess seed layer.

6. The method of claim 1, wherein the metal grid lines are formed by a process selected from the group consisting of screen printing, inkjet printing, and laser direct writing. The method comprises the following steps: preparing a patterned high-temperature-resistant mask plate according to the shape of the seed layer to be formed; placing the high-temperature-resistant mask plate on the one side of the cell substrate; using physical vapor deposition method, making the target material pass through the patterned area of the high-temperature-resistant mask plate to deposit the target material on the one side of the cell substrate to form the seed layer.

7. The method of claim 6, wherein: The patterned high-temperature-resistant mask plate refers to the slits on the high-temperature-resistant mask plate with the shape of the seed layer to be formed; the width of the slits is 1.5-50 times the width of the metal grid lines to be formed.

8. The method of claim 6, wherein the metal grid lines are formed by a process selected from the group consisting of screen printing, inkjet printing, and laser direct writing. The method further comprises the following steps: removing the high-temperature-resistant mask plate; forming a patterned second mask layer on the one side of the cell substrate; electroplating metal on the patterned area of the second mask layer to form the metal grid lines on the seed layer; removing the patterned second mask layer; etching away the excess seed layer.

9. The method of claim 6, wherein the metal grid lines are formed by a process selected from the group consisting of screen printing, inkjet printing, and laser direct writing. 5 The high-temperature-resistant mask plate is a first mask plate, and the first mask plate cooperates with a carrier to form the seed layer on the one side of the cell substrate; The carrier comprises a bearing part for bearing the cell substrate, and the bearing part is a groove on the carrier, the shape of the groove being the same as or similar to the shape of the cell substrate; the first mask plate comprises a first patterned part, and the first patterned part is provided with a first patterned through hole; in use, the first patterned part extends into the groove to cooperate with the groove, and the outer contour shape of the first mask plate is the same as or similar to the shape of the groove, so that the outer peripheral sidewall of the first mask plate can abut against the inner wall of the groove.

10. The method of claim 9, wherein the metal grid lines are formed by a process selected from the group consisting of screen printing, inkjet printing, and laser direct writing. The first mask plate further comprises a first sidewall extending upward from the edge of the first patterning part, the first sidewall abuts the inner wall of the groove, and the upper end of the first sidewall is connected with an outwardly extending overlap; in use, the overlap is overlapped on the edge of the groove to limit the depth of the first patterning part extending into the groove.

11. The method of claim 10, wherein the metal grid lines are formed by a process selected from the group consisting of screen printing, inkjet printing, and laser direct writing. The outer wall of the first sidewall is at least partially a first inclined surface, the inner wall of the groove is at least partially a second inclined surface, and the first inclined surface and the second inclined surface cooperate with each other to enable the first mask plate and the groove to be engaged.

12. The method of claim 9, wherein the metal grid lines are formed by a process selected from the group consisting of screen printing, inkjet printing, and laser direct writing. The first patterning part is provided with a flexible material layer on the side facing the substrate of the battery piece, and / or the carrying part of the carrier is provided with a flexible material layer.

13. A method of fabricating a metal grid for a photovoltaic cell as claimed in any one of claims 9 to 12, wherein, The high-temperature-resistant mask plate further comprises a second mask plate, the second mask plate comprises a second patterning part, the second patterning part is provided with a second patterning through hole, and the carrying part of the carrier is provided with a penetrating hole; In use, the second patterning part of the second mask plate abuts the lower surface of the carrying part, so that the second patterning through hole is aligned with the penetrating hole to form a seed layer on the other side of the substrate of the battery piece.

14. The method of claim 1, wherein: the seed layer comprises a plurality of strip structures arranged at intervals on one side of the substrate of the battery piece, and the metal grid lines are formed on each of the strip structures; the width of the strip structure is D1, and the width of the metal grid line is D2, wherein D1 is greater than D2.

15. The method of claim 1, wherein: the seed layer comprises a plurality of strip structures arranged at intervals on one side of the substrate of the battery piece, and the metal grid lines are formed on each of the strip structures; the width of the strip structure is D1, the spacing between adjacent two strip structures is D3, and the ratio between D3 and D1 is 1-200.

16. The method of claim 1, wherein the metal grid lines are formed by a process selected from the group consisting of screen printing, ink jet printing, and laser direct writing. comprising the following steps: forming a seed layer on the region of the other side of the substrate of the battery piece where the metal grid lines are to be formed, the coverage area of the seed layer containing and being larger than the region where the metal grid lines are to be formed, and the seed layer not completely covering the other side of the substrate of the battery piece; forming metal grid lines on the seed layer, the metal grid lines not completely covering the seed layer; the one side of the substrate of the battery piece and the other side of the substrate of the battery piece are two opposite sides of the substrate of the battery piece.

17. A photovoltaic cell, characterized by obtained by the method of any one of claims 1-16.

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