Silicon wafer, battery piece and photovoltaic module

Abstract

The embodiment of the utility model provides a silicon wafer, a battery piece and a photovoltaic module. The silicon wafer comprises a first side edge, and a direction parallel to the first side edge is a first direction; wherein the first side edge is provided with a groove, a bent guide part is arranged at the joint of the groove and the first side edge, and the included angle between the tangent line of the guide part and the first direction is gradually increased or is firstly increased and then reduced in the direction from the groove opening to the groove bottom of the groove. According to the silicon wafer, stress concentration can be prevented from being formed at the notch, hidden crack and breakage risks of the silicon wafer are reduced, and edge breakage and battery piece breakage caused by collision between the welding strip and the notch of the groove in the installation process can be avoided. Therefore, hidden crack and breaking risks of the silicon wafer in the subsequent processing process can be reduced.

Description

Technical Field

[0001] This application belongs to the field of photovoltaic processing technology, specifically relating to a silicon wafer, a solar cell, and a photovoltaic module. Background Technology

[0002] Currently, in the manufacturing of photovoltaic modules, multiple cells are often connected in series, parallel, or a combination of both to increase the module's power output. However, when connecting multiple cells to form a string, the bent portions of the solder ribbon can get trapped between two cells, preventing adjacent cells from fitting tightly together.

[0003] In some implementations, the silicon wafers used to make the silicon substrates for batteries are structurally optimized, such as by designing rectangular grooves on the surface of the silicon wafers to accommodate the bends of the solder ribbons. However, this results in a significant increase in the breakage rate of the silicon wafers during manufacturing, or in the high breakage rate of the cells during the installation of the solder ribbons, making it impossible to mass-produce and use them. Utility Model Content

[0004] This application aims to provide a silicon wafer, a solar cell, and a photovoltaic module to solve or at least partially solve the problem of high breakage rates in existing silicon wafers and solar cells.

[0005] To solve the above-mentioned technical problems, this application is implemented as follows:

[0006] In a first aspect, this application discloses a silicon wafer, the silicon wafer including a first side edge, the direction parallel to the first side edge being a first direction; wherein, the first side edge is provided with a groove, and a curved guide portion is provided at the connection between the groove and the first side edge, and along the direction from the groove opening to the groove bottom, the angle between the tangent of the guide portion and the first direction gradually increases or first increases and then decreases.

[0007] In this embodiment, a groove for threading the solder ribbon is provided on the first side of the silicon wafer. A curved guide portion is provided at the connection between the groove and the first side. Along the direction from the groove opening to the bottom, the angle between the tangent of the guide portion and the first direction gradually increases or initially increases and then decreases. Providing a curved guide portion at the groove opening not only avoids stress concentration at the groove opening, reducing the risk of microcracks and breakage of the silicon wafer itself, but also guides any misaligned solder ribbon during insertion into the groove, quickly guiding it into the groove. This also prevents the solder ribbon from colliding with the groove opening during installation, thus avoiding edge chipping and cell breakage. Therefore, the risk of microcracks and breakage of the silicon wafer during subsequent processing can be reduced.

[0008] Optionally, the curved guide portion includes a guide portion with an arc-shaped cross-section along the first direction; the angle between the tangent of the guide portion and the first direction gradually increases; or, the curved guide portion includes a guide portion with an S-shaped cross-section along the first direction; the angle between the tangent of the guide portion and the first direction first increases and then decreases.

[0009] Optionally, the groove further includes a first groove bottom disposed between the two guide portions; the first groove bottom 22 has an arc-shaped cross-section along a first direction; the first groove bottom is connected to the two guide portions. By setting the groove bottom to an arc-shaped groove bottom, it is beneficial to reduce stress concentration at the corners of the groove bottom, thereby reducing the risk of microcracks and fragmentation of the silicon wafer.

[0010] Optionally, the groove further includes a second groove bottom disposed between the two guide portions, the second groove bottom having a straight cross-section along the first direction; and arc-shaped transition portions provided on both sides of the second groove bottom along the first direction. The transition portions can be used to avoid stress concentration at both ends of the second groove bottom along the first direction, reducing the risk of fragmentation of the silicon wafer.

[0011] Optionally, the groove further includes two groove walls perpendicular to the first direction, with the second groove bottom located between the two groove walls and parallel to the first direction; wherein the transition portion is disposed between the second groove bottom and the groove walls. By providing two groove walls between the first side and the second groove bottom, the overall depth of the groove is increased, which facilitates the accommodation of thicker welding strips and also prevents the welding strips from detaching from the groove, thus improving the installation stability of the welding strips within the groove.

[0012] Optionally, the silicon wafer includes a first surface and a second surface disposed opposite to each other along its thickness direction, the first side is connected between the first surface and the second surface, and the groove penetrates through the first surface and the second surface; both the first surface and the second surface are provided with line marks; wherein, along the direction from the groove opening to the bottom of the groove, the angle between the tangent of the guide portion and the extension direction of the line mark gradually increases or first increases and then decreases.

[0013] Optionally, the surface of the groove is formed with multiple grooves, the direction of which is parallel to the thickness direction of the silicon wafer. This way, when the solder strip is bent within the groove, the direction of the solder strip at the bend is parallel to the groove direction, which reduces the resistance to stretching the solder strip along its length, thus improving the installation accuracy and efficiency of the solder strip within the groove.

[0014] Secondly, this application also discloses a solar cell, the solar cell comprising a silicon substrate made of the silicon wafer: the silicon substrate includes a first side edge, and a direction parallel to the first side edge is a first direction; wherein,

[0015] The first side is provided with a groove, and a curved guide is provided at the connection between the groove opening and the first side. Along the direction from the groove opening to the bottom of the groove, the angle between the tangent of the guide and the first direction gradually increases or first increases and then decreases.

[0016] Thirdly, this application also discloses a photovoltaic module, which includes: a solder ribbon and a plurality of the above-described solar cells; the solder ribbon is at least partially located within the groove and connected between two adjacent solar cells.

[0017] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0019] Figure 1 This is a schematic diagram of the structure of a silicon wafer according to an embodiment of this application;

[0020] Figure 2 yes Figure 1 A magnified structural diagram of position A on the silicon wafer shown;

[0021] Figure 3 This is a partial structural diagram of another silicon wafer according to an embodiment of this application.

[0022] Reference numerals: 1 - silicon wafer, 11 - first side edge, 12 - line mark, 2 - groove, 21 - guide part, 22 - first groove bottom, 23 - second groove bottom, 24 - transition part, 25 - groove wall, x - first direction, y - second direction. Detailed Implementation

[0023] The embodiments of this utility model will now be described in detail. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0024] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0025] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0026] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0027] Reference Figure 1 This shows a schematic diagram of the structure of a silicon wafer according to an embodiment of this application, with reference to... Figure 2 , showed Figure 1 The diagram shows an enlarged view of the structure at position A on the silicon wafer. (See attached image.) Figure 1 and Figure 2 As shown, the silicon wafer may specifically include: a first side 11, with a first direction x parallel to the first side 11; wherein, the first side 11 is provided with a groove 2, and a curved guide portion 21 is provided at the connection between the groove 2 and the first side 11. Along the direction from the groove opening to the bottom of the groove 2, the angle between the tangent of the guide portion 21 and the first direction x gradually increases or first increases and then decreases.

[0028] In this embodiment, the first side 11 of the silicon wafer is provided with a groove 2 for the solder ribbon to pass through. A curved guide portion 21 is provided at the connection between the groove 2 and the first side 11. Along the direction from the groove opening to the bottom of the groove 2, the angle between the tangent of the guide portion 21 and the first direction x gradually increases or initially increases and then decreases. Providing a curved guide portion 21 at the groove opening of the groove 2 not only avoids stress concentration at the groove opening, reducing the risk of microcracks and breakage of the silicon wafer itself, but also guides the solder ribbon that has shifted during insertion into the groove 2, quickly guiding it into the groove 2. This also prevents the solder ribbon from colliding with the groove opening during installation, thus avoiding edge chipping and cell breakage. Therefore, the risk of microcracks and breakage of the silicon wafer during subsequent processing can be reduced.

[0029] In specific applications, the silicon wafer can be manufactured using a process of slicing a square silicon rod. Before slicing, the groove 2 can be formed on one side surface of the square silicon rod. During the process of slicing the square silicon rod using a dicing wire, the dicing wire can be positioned relative to the silicon rod along... Figure 1 The cutting line moves in the first direction x and feeds along the second direction y. In the region where the cutting line contacts the groove 2 opening, the force applied by the cutting line to the groove 2 opening can include a force along the first direction x and a force along the second direction y.

[0030] In practical applications, if a guide portion 21 is not provided at the connection between the groove opening of the groove 2 and the first side 11, the force applied to the groove opening of the groove 2 along the cutting line movement direction will easily cause defects such as chipping and poor edge quality at the groove opening due to the lack of silicon wafer body to offset the force. This results in irregular edges of the groove when it is cut into silicon wafers, such as gaps, which in turn increases the risk of microcracks and fragmentation of the entire silicon wafer. However, in this embodiment, since a curved guide portion 21 is provided at the groove opening of the groove 2, the depth of the guide portion 21 in the y-direction is relatively small compared to the total groove depth during silicon wafer cutting. The force applied to the groove opening of the groove 2 along the cutting line movement direction can be better distributed to the silicon wafer body facing the bottom of the groove, reducing stress concentration at the cutting line and the groove opening of the groove 2 and reducing the risk of chipping at the edge of the groove opening of the groove 2.

[0031] Furthermore, during the process of inserting the solder ribbon into the groove 2, there is a deviation in the x-direction when the solder ribbon and the groove opening are initially aligned. Therefore, the solder ribbon typically moves along the first x-direction on the first side 11 and eventually becomes at least partially fixed in the groove 2. Because a curved guide portion 21 is provided at the connection between the groove opening of the groove 2 and the first side 11, the solder ribbon can smoothly enter the groove 2 along the guide portion 21, greatly improving the speed at which the solder ribbon is inserted into the groove 2. Moreover, it avoids the risk of silicon wafer microcracks and breakage caused by the collision between the solder ribbon and the groove opening of the groove 2, as is present in the prior art.

[0032] In practical applications, after the silicon wafer is processed into a battery cell, the solder strip inserted into the groove 2 can be a round wire solder strip with a diameter of 0.25 mm. The bend of the round wire solder strip corresponding to the first side 11 can be pre-flattened. The width of the solder strip at the flattened part is 0.52-0.587 mm. To facilitate the insertion of the flattened solder strip into the groove 2, the size of the groove 2 must be larger than the above dimensions.

[0033] Specifically, during the installation of the welding strip, a stringer can be used to place one end of the welding strip onto the grid line of the first solar cell and initially align it with the groove 2. Then, the welding strip is cut, and another solar cell is placed and connected to the cut section. Therefore, after installation, the welding strip will experience tensile stress along its length. When the gap between solar cells is further reduced, the stress on the solar cell at the bend of the welding strip is greater, which can lead to microcracks in the solar cell. Therefore, grooves 2 need to be provided on the solar cell to ensure a smooth transition of the welding strip.

[0034] Optionally, the width of the groove 2 along the first direction x is 1-1.5 mm, and the depth of the groove 2 is 0.5-1 mm. That is, the width of the groove 2 is greater than the width of the bent welding strip, and the depth of the groove 2 is greater than the thickness of the welding strip, so as to accommodate the bent welding strip into the groove 2.

[0035] In some optional embodiments of this application, the curved guide portion 21 may include a guide portion with an arc-shaped cross-section along the first direction x, for example, forming an arc-shaped guide portion; the angle between the tangent of the arc-shaped guide portion and the first direction x gradually increases to avoid the welding strip colliding with the groove opening of the groove 2 during installation. The gradually increasing angle between the tangent of the arc-shaped guide portion and the first direction x facilitates the rapid introduction of the welding strip into the groove 2.

[0036] In practical applications, the cross-sectional shape of the arc-shaped guide can include a quarter-circle arc or a minor arc. When the arc of the arc-shaped guide is less than or equal to a quarter-circle arc, the angle between the tangent of the arc-shaped guide and the first direction x gradually increases. At this time, in the contact area between the diamond wire and the groove edge, the force applied to the groove 2 by the diamond wire along the cutting line movement direction, and the force applied to the groove 2 by the diamond wire along the feed direction (i.e., the y-direction), can be well distributed to the silicon wafer body, thereby reducing defects caused by excessive stress in the contact area between the diamond wire and the groove edge.

[0037] Optionally, the radius of the arc-shaped guide is 0.3-0.5 mm, and the radian is 0-π / 2. This allows the angle between the tangent of the arc-shaped guide and the first direction x to gradually increase, and also allows the size of the arc-shaped guide to be controlled within a reasonable range. This achieves the goal of guiding the solder strip into the groove 2 while avoiding the problem of the overall size of the groove 2 being too large. Simultaneously, it also reduces the high fragmentation rate during slicing after the silicon rod has been grooved.

[0038] For example, the radius of the arc-shaped guide can be any one of 0.3 mm, 0.35 mm, 0.42 mm or 0.5 mm, and the curvature of the arc-shaped guide can be π / 4, π / 3, π3 / 8 or π / 2, etc. The embodiments of this application do not specifically limit the radius and curvature of the arc-shaped guide.

[0039] In some alternative embodiments of this application, the curved guide portion 21 may include an S-shaped guide portion 21 in cross section along the first direction x; the angle between the tangent of the guide portion 21 and the first direction x tends to increase first and then decrease. The S-shaped guide portion 21 can provide a longer guide path for the welding strip, which is beneficial to further improve the efficiency of installing the welding strip in the groove 2.

[0040] In practical applications, the angle between the tangent of the S-shaped guide portion 21 and the first direction x tends to increase first and then decrease. In addition to providing a longer guide path when installing solder strips, during silicon wafer processing, the force applied to the groove 2 opening along the cutting line movement direction can be better distributed to the silicon wafer body facing the bottom of the groove, reducing stress concentration at the cutting line and the groove 2 opening and reducing the risk of edge chipping at the groove 2 opening edge.

[0041] Based on the above embodiments of this application or other alternative embodiments, such as Figure 2As shown, the groove 2 may further include a first groove bottom 22 disposed between the two guide portions 21; the first groove bottom 22 has an arc-shaped cross-section along the first direction x, for example, the first groove bottom 22 can be an arc-shaped groove bottom; the first groove bottom 22 is connected to the two guide portions 21. In specific applications, by setting the groove bottom of the groove 2 as... Figure 2 The first groove bottom 22 shown helps to reduce stress concentration at the corner of the groove bottom 2, thereby reducing the risk of microcracks and fragmentation of the silicon wafer.

[0042] Optionally, the radius of the first groove bottom 22 can be 0.5-1 mm, and the arc is π / 2-π. In this way, the overall depth and width of the groove 2 can be controlled within a reasonable range, which can both install the welding strip in the groove 2 and ensure the installation accuracy of the string welding machine.

[0043] For example, the radius of the first groove bottom 22 can be any one of 0.5 mm, 0.65 mm, 0.8 mm or 1 mm, and the arc of the first groove bottom 22 can be π / 2, π2 / 3, π7 / 8 or π, etc. The embodiments of this application do not specifically limit the radius and arc of the first groove bottom 22.

[0044] In practical applications, if the groove 2 is a traditional square groove, when machining the groove 2 on a square silicon rod, the silicon material at the predetermined groove 2 needs to be removed layer by layer by a grinding wheel. This requires applying force in both the depth and width directions of the groove 2, resulting in high stress at the bottom tip of the groove 2. When slicing the square silicon rod, the force applied to the edge of the groove 2 along the cutting line is not offset by the silicon wafer itself. Combined with the relatively high stress generated during the machining of the groove 2, this leads to a high breakage rate. The first groove bottom 22 of this application can effectively avoid the above problems.

[0045] Experimental data shows that by providing a curved guide portion 21 at the connection between the groove opening and the first side 11 of the groove 2, and by setting the bottom of the groove 2 as the first groove bottom 22, the microcracks of the silicon wafer and the solar cell can be effectively reduced. Specifically, the breakage rate at the silicon wafer end is less than 0.3%, and the breakage rate at the module end is less than 0.5%. Compared to existing technologies that do not provide the guide portion 21 at the groove opening (where the breakage rate at the silicon wafer end is greater than 20% and the breakage rate at the module end is greater than 30%), the technical solution described in this application significantly reduces the silicon wafer breakage rate.

[0046] Based on the above embodiments of this application or some other optional embodiments, refer to Figure 3 This illustrates a partial structural diagram of a silicon wafer according to an embodiment of this application, as shown below. Figure 3As shown, the groove 2 may also include a second groove bottom 23 disposed between the two guide portions 21. The second groove bottom 23 has a straight cross section along the first direction x. For example, the second groove bottom may be a planar groove bottom. The second groove bottom 23 is provided with arc-shaped transition portions 24 on both sides along the first direction x. The transition portions 24 can be used to avoid stress concentration at both ends of the second groove bottom 23 along the first direction x, thereby reducing the risk of fragmentation of the silicon wafer.

[0047] In practical applications, by setting the bottom of the groove 2 as the second bottom 23, the cross-sectional area of ​​the groove 2 can be increased without increasing the width of the groove 2 along the first direction x. This is beneficial for accommodating the bent welding strip and improving the installation stability of the welding strip in the groove 2.

[0048] Optionally, the curvature of the transition portion 24 is 0-π / 2, so that the size of the transition portion 24 is controlled within a reasonable range. This can avoid stress concentration at both ends of the second groove bottom 23 along the first direction x, and facilitate the processing of the transition portion 24.

[0049] Optionally, such as Figure 3 As shown, the groove 2 may further include: two groove walls 25 perpendicular to the first direction x, a second groove bottom 23 located between the two groove walls 25, and the second groove bottom 23 being parallel to the first direction x; wherein, the transition portion 24 is disposed between the second groove bottom 23 and the groove walls 25.

[0050] In specific applications, by setting two groove walls 25 between the first side 11 and the second groove bottom 23, it is beneficial to increase the overall depth of the groove 2, thereby facilitating the accommodation of thicker welding strips and preventing the welding strips from coming out of the groove 2, thus improving the installation stability of the welding strips in the groove 2.

[0051] In practical applications, the groove wall 25 is closer to the bottom of the groove than the guide portion 21, and the groove wall 25 has a greater depth in the groove. During silicon wafer dicing, the force applied to the edge of the groove 2 along the dicing line can be distributed to the silicon wafer body near and away from the bottom of the groove, resulting in less stress concentration at the dicing line and the groove opening of the groove 2. Therefore, the groove wall 25 can be perpendicular to the first direction x, or approximately perpendicular to the first direction x; for example, the angle between the groove wall 25 and the first direction x is between 80° and 90°.

[0052] Specifically, during slicing, when the diamond wire cuts into the groove wall 25 region, the silicon wafer body away from the bottom of the groove can withstand a greater force than when the diamond wire cuts into the guide portion 21 region of the groove, the silicon wafer body away from the bottom of the groove. When the groove wall 25 is perpendicular to or approximately perpendicular to the first direction x, there is no risk of edge chipping at the groove wall.

[0053] In some optional embodiments of this application, the silicon wafer includes a first surface and a second surface disposed opposite to each other along its thickness direction, the first side edge connecting between the first surface and the second surface, and the groove penetrating through the first surface and the second surface. Both the first surface and the second surface are provided with... Figure 1 The line mark 12 shown; wherein, along the direction from the opening to the bottom of the groove 2, the angle between the tangent of the guide portion 21 and the extension direction of the line mark 12 gradually increases or first increases and then decreases.

[0054] In practical applications, the extension direction of the wire mark 12 is basically parallel to the length direction of the first side 11, or the extension direction of one side of the wire mark 12 forms a very small angle with the first side 11, specifically less than 15°. When the angle between the tangent of the guide portion 21 and the extension direction of one side of the wire mark 12 gradually increases or first increases and then decreases, correspondingly, making the angle between the tangent of the guide portion 21 and the first direction x gradually increase or first increases and then decreases is beneficial for guiding the installation of the solder strip by the guide portion 21. The wire mark 12 mainly originates from the traces left on the silicon wafer surface during diamond wire processing. The direction of the wire mark 12 is close to the movement direction of the diamond wire. By limiting the angle between the wire mark 12 and the guide portion 21 of the groove, the change in the angle between the movement direction of the diamond wire and the guide portion 21 of the groove can be determined, controlling the force exerted by the diamond wire on the edge of the groove during silicon wafer processing, thus reducing the breakage rate.

[0055] Optionally, the surface of the groove 2 is formed with multiple grooves, the direction of which is parallel to the thickness direction of the silicon wafer. This way, when the solder strip is bent within the groove 2, the direction of the solder strip at the bend is parallel to the groove direction, which reduces the resistance to stretching the solder strip along its length, thus improving the installation accuracy and efficiency of the solder strip within the groove 2.

[0056] In practical applications, during the fabrication of the groove 2 on the silicon wafer, grooves can be first etched on a square silicon rod, with the length direction of the square silicon rod parallel to the groove direction of the groove 2. During slicing, slicing is performed perpendicular to the length direction of the square silicon rod, with the side of the square silicon rod containing the groove 2 serving as the cutting surface. During slicing, the direction of the cutting line is the direction of the line mark 12. When the angle between the line mark 12 and the tangent of the left or right guide portion 21 of the groove 2 is set to first increase and then decrease, the angle between the cutting line and the tangent of the guide portion 21 can be made to first increase and then decrease, avoiding excessively large angles between the cutting line and the tangent of the guide portion 21 at the beginning, which could lead to edge chipping of the groove 2.

[0057] In summary, the silicon wafer described in the embodiments of this application may include at least the following advantages:

[0058] In this embodiment, a groove for threading the solder ribbon is provided on the first side of the silicon wafer. A curved guide portion is provided at the connection between the groove and the first side. Along the direction from the groove opening to the bottom, the angle between the tangent of the guide portion and the first direction gradually increases or initially increases and then decreases. Providing a curved guide portion at the groove opening not only avoids stress concentration at the groove opening, reducing the risk of microcracks and breakage of the silicon wafer itself, but also guides any misaligned solder ribbon during insertion into the groove, quickly guiding it into the groove. This also prevents the solder ribbon from colliding with the groove opening during installation, thus avoiding edge chipping and cell breakage. Therefore, the risk of microcracks and breakage of the silicon wafer during subsequent processing can be reduced.

[0059] This application also provides a solar cell, which includes a silicon substrate made of silicon wafer as described in any of the above embodiments. The silicon substrate includes a first side, and a direction parallel to the first side is a first direction. The first side has a groove, and a curved guide portion is provided at the connection between the groove and the first side. Along the direction from the groove opening to the bottom, the angle between the tangent of the guide portion and the first direction gradually increases or first increases and then decreases. Specifically, the solar cell can be made of silicon wafer as described in any of the above embodiments.

[0060] It should be noted that, in the embodiments of this application, the specific structure of the groove in the silicon substrate of the battery cell is the same as the specific structure of the groove in the silicon wafer described in any of the above embodiments, and its beneficial effects are also similar, so it will not be described again here.

[0061] This application also provides a photovoltaic module, which includes: a solder ribbon and the solar cells described in the above embodiments; the solder ribbon is at least partially located within the groove and connected between two adjacent solar cells. The module can specifically be made using the solar cells described in any of the above embodiments.

[0062] It should be noted that in the embodiments of this application, the specific structure of the battery cell in the component is the same as that of the battery cell described in any of the above embodiments, and its beneficial effects are also similar, so it will not be described in detail here.

[0063] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

Claims

1. A silicon wafer, characterized in that, The silicon wafer (1) includes a first side (11), and the direction parallel to the first side (11) is a first direction (x); wherein, The first side (11) is provided with a groove (2), and a curved guide (21) is provided at the connection between the groove (2) and the first side (11); along the direction from the groove opening to the bottom of the groove (2), the angle between the tangent of the guide (21) and the first direction (x) gradually increases or first increases and then decreases.

2. The silicon wafer according to claim 1, characterized in that, The curved guide portion (21) includes a guide portion with an arc-shaped cross section along the first direction (x); the angle between the tangent of the guide portion and the first direction (x) gradually increases. Alternatively, the curved guide portion (21) includes a guide portion with an S-shaped cross section along the first direction (x); the angle between the tangent of the guide portion (21) and the first direction (x) tends to increase first and then decrease.

3. The silicon wafer according to claim 2, characterized in that, The groove (2) further includes a first groove bottom (22) disposed between the two guide portions (21); the first groove bottom (22) has an arc-shaped cross section along the first direction (x); the first groove bottom (22) is connected to the two guide portions (21).

4. The silicon wafer according to claim 3, characterized in that, The radius of the first groove bottom (22) is 0.5-1 mm, and the arc is π / 2-π.

5. The silicon wafer according to claim 2, characterized in that, The groove (2) further includes a second groove bottom (23) disposed between the two guide portions (21); the second groove bottom (23) has a straight cross section along the first direction (x); the second groove bottom (23) has arc-shaped transition portions (24) on both sides along the first direction (x).

6. The silicon wafer according to claim 5, characterized in that, The groove (2) further includes: two groove walls (25) perpendicular to the first direction (x), the second groove bottom (23) being located between the two groove walls (25), and the second groove bottom (23) being parallel to the first direction (x); wherein, The transition section (24) is disposed between the second bottom (23) of the tank and the tank wall (25).

7. The silicon wafer according to claim 5, characterized in that, The radius of the transition section (24) is 0 - π / 2.

8. The silicon wafer according to claim 2, characterized in that, The radius of the arc-shaped guide is 0.3-0.5 mm, and the radian is 0-π / 2.

9. The silicon wafer according to claim 1, characterized in that, The groove (2) has a width of 1-1.5 mm along the first direction (x) and a recess depth of 0.5-1 mm.

10. The silicon wafer according to claim 1, characterized in that, The silicon wafer includes a first surface and a second surface disposed opposite to each other along its thickness direction, a first side edge connecting the first surface and the second surface, and a groove penetrating the first surface and the second surface; the first surface and the second surface include line marks (12); wherein, Along the direction from the opening of the groove (2) to the bottom of the groove, the angle between the tangent of the guide part (21) and the extension direction of the line mark (12) gradually increases or first increases and then decreases.

11. The silicon wafer according to claim 1, characterized in that, The surface of the groove (2) has multiple grooves, the direction of which is parallel to the thickness direction of the silicon wafer.

12. A battery cell, characterized in that, The solar cell comprises: a silicon substrate made of a silicon wafer according to any one of claims 1 to 11, the silicon substrate including a first side (11), and a direction parallel to the first side (11) being a first direction (x); wherein, The first side (11) is provided with a groove (2), and a curved guide (21) is provided at the connection between the groove (2) and the first side (11). Along the direction from the groove opening to the bottom of the groove (2), the angle between the tangent of the guide (21) and the first direction (x) gradually increases or first increases and then decreases.

13. A photovoltaic module, characterized in that, The photovoltaic module includes: a solder ribbon and a plurality of solar cells as claimed in claim 12; the solder ribbon is at least partially located within the groove (2) and connected between two adjacent solar cells.

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