Back contact cell and photovoltaic module

Abstract

The invention provides a back contact battery and a photovoltaic module. The back contact battery comprises a battery body; the multiple first auxiliary grids and the multiple second auxiliary grids are located on the battery body, the first auxiliary grids and the second auxiliary grids extend in the first direction and are alternately arranged at intervals in the second direction, and the distance between every two adjacent auxiliary grid sections in the first direction is a first distance; the plurality of first insulating parts are positioned on one side, far away from the battery body, of the plurality of auxiliary grid sections and are arranged at intervals along the first direction, and the distance between the projections of the end parts of the auxiliary grid sections on the battery body along the first direction and two adjacent first insulating parts is a second distance; the plurality of welding parts are positioned on one side, far away from the battery body, of the auxiliary grid section; the difference between the first distance and the second distance is greater than or equal to 0.3 mm, and the difference between the second distance and the width of the welding part in the first direction is greater than or equal to 0.3 mm, so that the problems of deviation, splitting or non-plump form and the like of the welding flux after solidification are avoided, and the welding reliability is ensured.

Description

Technical Field

[0001] The present application relates to the field of solar energy technology, and in particular to a back contact cell and a photovoltaic module. Background Art

[0002] In the current manufacturing process of back-contact batteries, there are problems such as offset, splitting or incomplete shape after the solder paste or putty is cured, resulting in poor welding reliability. Summary of the invention

[0003] The main purpose of the present application is to provide a back-contact cell and a photovoltaic module to at least solve the problem of poor welding reliability of solder paste or gray glue of back-contact cells in the prior art.

[0004] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a back-contact battery is provided, comprising: a battery body; a plurality of first sub-grids and a plurality of second sub-grids, which are located on the battery body, the first sub-grids and the second sub-grids extend along a first direction and are arranged alternately and spaced along a second direction, the first sub-grids and the second sub-grids have different polarities, the first direction intersects with the second direction, the first sub-grids and the second sub-grids each include a plurality of sub-grid segments arranged at intervals along the first direction, and the distance between two adjacent sub-grid segments along the first direction is a first distance; a plurality of first insulating portions, which are located on a side of the plurality of sub-grid segments away from the battery body and are arranged at intervals along the first direction, the projection of the end of the sub-grid segment on the battery body is located in the projection of the first insulating portion on the battery body, and the distance between two adjacent first insulating portions along the first direction is a second distance; a plurality of welding portions, which are located on a side of the sub-grid segment away from the battery body, and the welding portion is located between two adjacent first insulating portions along the first direction; the difference between the first distance and the second distance is greater than or equal to 0.3 mm, and the difference between the second distance and the width of the welding portion in the first direction is greater than or equal to 0.3 mm.

[0005] Optionally, the auxiliary gate segment corresponds one-to-one to the first insulating part, the distance between two adjacent auxiliary gate segments along the second direction is a third distance, the distance between the edge of the first insulating part and the corresponding auxiliary gate segment is a fourth distance, and the difference between the third distance and the fourth distance is greater than or equal to 0.15 mm.

[0006] Optionally, the first insulating portion is symmetrical about the secondary gate segment axis.

[0007] Optionally, a width of the first insulating portion in the second direction is 0.2-0.6 mm.

[0008] Optionally, the back contact battery further includes: a plurality of main grids extending along the second direction and arranged at intervals along the first direction, the main grid being located between two adjacent auxiliary grid segments along the first direction, and the welding portion covering a portion of the main grid.

[0009] Optionally, the polarity of the main grid is the same as the polarity of the first sub-grid, the sub-grid segment of the second sub-grid is a second sub-grid segment, and the back-contact battery also includes: a plurality of second insulating parts, extending along the first direction and arranged at intervals along the second direction, the sub-grid segments, the second insulating parts and the main grid are arranged in a direction away from the battery body, the projections of the ends of two adjacent second sub-grid segments along the first direction on the battery body are located in the projection of the second insulating part on the battery body, and the projection of the main grid on the battery body overlaps with the projection of the second insulating part on the battery body.

[0010] Optionally, the plurality of second insulating parts include a plurality of edge insulating parts and a plurality of non-edge insulating parts, and a minimum distance between the edge insulating part and a surface edge of the battery body is smaller than a minimum distance between the non-edge insulating part and the surface edge.

[0011] Optionally, widths of the edge insulating portion, the non-edge insulating portion and the first insulating portion in the first direction decrease sequentially.

[0012] Optionally, the width of the edge insulating portion in the first direction is 3 to 20 mm, and the width of the non-edge insulating portion in the first direction is 2 to 20 mm.

[0013] In order to achieve the above-mentioned object, according to one aspect of the present application, a photovoltaic module is provided, comprising: any one of the back contact cells described above.

[0014] By applying the technical solution of the present application, the dimensional relationship between the auxiliary grid line segment, the first insulating part and the welding part is quantified in the screen design, and the difference between the first distance and the second distance is limited to be greater than or equal to 0.3 mm, and the difference between the second distance and the width of the welding part in the first direction is greater than or equal to 0.3 mm, wherein the first distance is the distance between two adjacent auxiliary grid segments along the first direction, and the second distance is the distance between two adjacent first insulating parts along the first direction, thereby ensuring that the shape of the welding part after solidification is better, avoiding problems such as displacement, splitting or incomplete shape of the solder after solidification, and ensuring better welding reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings constituting part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0016] Figure 1 A schematic diagram of the local structure of a back contact battery provided according to an embodiment of the present application is shown;

[0017] Figure 2 A schematic diagram of the local structure of another back contact battery provided according to an embodiment of the present application is shown;

[0018] Figure 3 A schematic diagram showing the welding effect of a comparative example 1 of a back contact battery provided according to an embodiment of the present application is shown;

[0019] Figure 4 A schematic diagram showing the welding effect of Comparative Example 2 of another back contact battery provided according to an embodiment of the present application is shown;

[0020] Figure 5 A schematic diagram of the welding effect of Example 1 of a back contact battery provided according to an embodiment of the present application is shown;

[0021] Figure 6 A schematic diagram of the welding effect of another back-contact battery embodiment 2 provided according to an embodiment of the present application is shown.

[0022] The above drawings include the following reference numerals:

[0023] 1. Battery body; 2. First auxiliary grid; 3. Second auxiliary grid; 4. Auxiliary grid segment; 5. First insulating part; 6. Welding part; 7. Main grid; 42. First auxiliary grid segment; 43. Second auxiliary grid segment; 8. Second insulating part; 81. Edge insulating part; 82. Non-edge insulating part. DETAILED DESCRIPTION

[0024] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0025] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0026] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0027] As introduced in the background technology, there is a problem in the prior art that the solder paste or gray glue of the back contact battery has poor welding reliability. To solve this technical problem, the embodiments of the present application provide a back contact battery and a photovoltaic module.

[0028] The present application embodiment provides a back contact battery, such as Figure 1 As shown, the above-mentioned back contact battery includes:

[0029] Battery body 1;

[0030] A plurality of first sub-grids 2 and a plurality of second sub-grids 3 are located on the battery body 1, the first sub-grids 2 and the second sub-grids 3 extend along a first direction x and are alternately arranged along a second direction y, the first sub-grids 2 and the second sub-grids 3 have different polarities, the first direction x intersects with the second direction y, the first sub-grids 2 and the second sub-grids 3 each include a plurality of sub-grid segments 4 arranged along the first direction x, and the distance between two adjacent sub-grid segments 4 along the first direction x is a first distance a;

[0031] A plurality of first insulating portions 5 are located on a side of the plurality of auxiliary grid segments 4 away from the battery body 1 and are arranged at intervals along the first direction x. The projection of the end of the auxiliary grid segment 4 on the battery body 1 is located in the projection of the first insulating portion 5 on the battery body 1. The distance between two adjacent first insulating portions 5 along the first direction x is a second distance c.

[0032] A plurality of welding portions 6 are located on a side of the auxiliary grid segment 4 away from the battery body 1 , and the welding portion 6 is located between two adjacent first insulating portions 5 along the first direction x;

[0033] The difference between the first distance a and the second distance c is greater than or equal to 0.3 mm, for example, ac=0.3 mm, or ac=0.5 mm, or ac=0.7 mm, or ac=0.9 mm, etc. The difference between the second distance c and the width b of the welding portion 6 in the first direction x is greater than or equal to 0.3 mm, for example, cb=0.3 mm, or cb=0.6 mm, cb=0.9 mm, or cb=1.1 mm.

[0034] Through the above embodiments, the dimensional relationship between the auxiliary grid line segment, the first insulating part and the welding part is quantified in the screen design, and the difference between the first distance and the second distance is limited to be greater than or equal to 0.3mm, and the difference between the second distance and the width of the welding part in the first direction is greater than or equal to 0.3mm, wherein the first distance is the distance between two adjacent auxiliary grid segments along the first direction, and the second distance is the distance between two adjacent first insulating parts along the first direction, thereby ensuring that the shape of the welding part after solidification is better, avoiding problems such as displacement, splitting or incomplete shape of the solder after solidification, and ensuring better welding reliability.

[0035] Back contact cell, also known as interdigitated back contact (IBC) cell, is a new type of solar cell structure. Its most notable feature is that the PN junction and the positive and negative electrodes are designed on the back of the cell, thus forming an unobstructed area on the front. Since there is no obstruction on the front, the IBC cell can absorb sunlight more effectively, thereby achieving a higher photoelectric conversion efficiency. In the IBC cell, the P-type region and the N-type region are alternately arranged on the back of the cell, and the P-type region and the N-type region are isolated from each other.

[0036] In some optional implementations, the polarity of one of the first sub-grid 2 and the second sub-grid 3 is positive, and the polarity of the other of the first sub-grid 2 and the second sub-grid 3 is negative.

[0037] In some optional embodiments, the first auxiliary grid 2 and the second auxiliary grid 3 can be sintered by a burn-through paste, and a metal paste is printed on a part of the passivation layer surface by a screen printing process, and the metal paste can include at least one of silver, aluminum, copper, tin or nickel for conduction and support. The first insulating portion 5 can isolate different electrodes.

[0038] In some optional embodiments, the welding portion 6 can realize electrical connection between components in the back contact battery, specifically, realize electrical connection between the main grid and the auxiliary grid with the same properties as the main grid. The material of the welding portion 6 can be aluminum, tin, or gray glue, but it is not limited to the above types. Those skilled in the art can also reasonably select the material of the welding portion according to actual needs, and this application does not make specific limitations.

[0039] In some optional embodiments, the first insulating portion 5 can achieve insulation between components in the back contact battery, specifically, insulating and isolating the main grid and the auxiliary grid with different properties from the main grid, to avoid the problem of short circuit caused by the main grid and the auxiliary grid with different properties from the main grid being connected. The first insulating portion 5 can be made of silica gel or insulating glue, but is not limited to the above types. Those skilled in the art can also reasonably select the material of the first insulating portion according to actual needs, and this application does not make specific limitations.

[0040] In some optional embodiments, such as Figure 1 As shown, the above-mentioned auxiliary gate segments 4 correspond one-to-one to the first insulating part 5, and the distance between two adjacent auxiliary gate segments 4 along the second direction y is a third distance s / 2, that is, the distance between two auxiliary gate segments with different polarities is the third distance s / 2, and the distance between the edge of the first insulating part 5 and the corresponding auxiliary gate segment 4 is a fourth distance h / 2, and the difference between the third distance s / 2 and the fourth distance h / 2 is greater than or equal to 0.15mm, for example, s / 2-h / 2=0.15mm, or s / 2-h / 2=0.3mm, or s / 2-h / 2=0.45mm, or s / 2-h / 2=0.6mm, or s / 2-h / 2=0.7mm, etc. In the above embodiment, due to the material characteristics of the first insulating part, flow is likely to occur when printing the first insulating part. Setting s / 2-h / 2≥0.15mm can not only ensure that the first insulating part effectively covers the corresponding sub-gate segment, but also prevent the first insulating part from covering the non-corresponding sub-gate segment due to offset, thereby ensuring that the first insulating part can achieve its isolation effect and avoiding the problem of the first insulating part being offset, split or having an incomplete shape after curing, which affects its isolation effect.

[0041] In some optional embodiments, such as Figure 1 As shown, the first insulating part 5 is symmetrical about the auxiliary gate segment 4. That is, the distances from the auxiliary gate segment 4 to the two opposite edges of the first insulating part 5 are the same. This layout reserves the same margin for the deviation of the first insulating part in two directions (positive y direction and negative y direction), which can further avoid the problem that the first insulating part cannot cover the corresponding auxiliary gate segment after solidification due to the fluidity of the first insulating part, or that the first insulating part covers the non-corresponding auxiliary gate segment after solidification, thereby further ensuring that the effect of the first insulating part after solidification is better.

[0042] In some optional embodiments, such as Figure 1As shown, the width of the first insulating portion 5 in the second direction y is 0.2-0.6 mm, for example, the width of the first insulating portion 5 is 0.2 mm, or 0.3 mm, or 0.4 mm, or 0.6 mm, etc. Setting the width of the first insulating portion in the second direction within this range can avoid the problem of wasting screen area due to the first insulating portion being too wide, and can also avoid the problem of short circuit due to the first insulating portion being too narrow to effectively isolate the main grid and the secondary grid segment different from the main grid.

[0043] In some optional embodiments, such as Figure 1 and Figure 2 As shown, the back contact battery further includes: a plurality of main grids 7 extending along the second direction y and arranged at intervals along the first direction x, the main grid 7 being located between two adjacent sub-grid segments 4 along the first direction x, and the welding portion 6 covering a portion of the main grid 7. In the above embodiment, the main grid is electrically connected to the sub-grid with the same polarity as the main grid through the welding portion, and the main grid is electrically isolated from the sub-grid with the opposite polarity as the main grid through the insulating portion.

[0044] Specifically, the main grid 7 may be located on a side of the welding portion 6 away from the auxiliary grid segment 4 .

[0045] In some optional embodiments, such as Figure 2 As shown, the polarity of the main grid 7 is the same as that of the first auxiliary grid 2, the auxiliary grid segment 4 of the second auxiliary grid 3 is the second auxiliary grid segment 43, and the back contact battery further includes: a plurality of second insulating portions 8 extending along the first direction x and arranged at intervals along the second direction y, the auxiliary grid segments 4, the second insulating portions 8 and the main grid 7 are arranged in a direction away from the battery body 1, the projections of the ends of two adjacent second auxiliary grid segments 43 along the first direction x on the battery body are located in the projections of the second insulating portions 8 on the battery body 1, and the projections of the main grid 7 on the battery body 1 overlap with the projections of the second insulating portions 8 on the battery body 1. In this embodiment, the polarity of the main grid and the second auxiliary grid are different, and the second insulating portion is located between the auxiliary grid line and the main grid, which can isolate the main grid and the second auxiliary grid to avoid short circuit problems; and the second auxiliary grid segment is disconnected at the second insulating portion, which can avoid electrical connection between the main grid and the second auxiliary grid when the second insulating portion is offset, split or has an incomplete shape, thereby avoiding short circuit problems.

[0046] like Figure 2 As shown, the auxiliary gate segment 4 of the first auxiliary gate 2 is a first auxiliary gate segment 42. One second insulating portion 8 corresponds to two auxiliary gate segments 4.

[0047] In some optional embodiments, such as Figure 2As shown, the plurality of second insulating parts 8 include a plurality of edge insulating parts 81 and a plurality of non-edge insulating parts 82, and the minimum distance between the edge insulating part 81 and the surface edge of the battery body 1 is smaller than the minimum distance between the non-edge insulating part 82 and the surface edge. In other words, compared with the second insulating part located at the non-edge position of the back contact battery, the second insulating part located at the edge position of the back contact battery is wider, which can prevent the head and tail welding strips of the battery string from being offset to the non-insulating part covering part with the adhesive film during the lamination process, resulting in overlapping of the opposite sex sub-grid, thereby causing the problem of short circuit.

[0048] In some optional embodiments, such as Figure 2 As shown, the widths of the edge insulating portion 81, the non-edge insulating portion 82 and the first insulating portion 5 in the first direction x are reduced in sequence. The edge insulating portion, the non-edge insulating portion and the first insulating portion are arranged in a direction from the edge of the battery body to the center of the battery body. By setting the width of the insulating portion to be larger from the center area to the edge area, the edge warping problem of the back contact battery can be avoided.

[0049] In some optional embodiments, such as Figure 2 As shown, the width of the edge insulating portion 81 in the first direction x is 3-20 mm, for example, the width of the edge insulating portion 81 is 3 mm, or 5 mm, or 10 mm, or 16 mm, or 20 mm, etc.; the width of the non-edge insulating portion 82 in the first direction x is 2-20 mm, for example, the width of the non-edge insulating portion 82 is 2 mm, or 5 mm, or 10 mm, or 15 mm, or 20 mm, etc. In this embodiment, the width of the edge insulating portion in the first direction is 3-20 mm, which can provide sufficient insulation protection for the auxiliary grid located at the edge of the back contact battery and having a different polarity from the main grid, which is beneficial to the overall stability of the back contact battery, and can avoid the problem of waste of screen area caused by excessive width; the width of the non-edge insulating portion in the first direction is 2-20 mm, which can provide sufficient insulation protection for the auxiliary grid located at the non-edge position of the back contact battery and having a different polarity from the main grid, which is beneficial to the overall stability of the back contact battery, and can avoid the problem of waste of screen area caused by excessive width; and the design of gradual width can slow down the warping of the battery cell.

[0050] An embodiment of the present application further provides a photovoltaic module, comprising: any one of the above-mentioned back-contact cells.

[0051] Through the above embodiments, the back-contact cell in the above photovoltaic module quantifies the size relationship between the auxiliary grid line segment, the first insulating part and the welding part, limits the difference between the first distance and the second distance to be greater than or equal to 0.3mm, and the difference between the second distance and the width of the welding part in the first direction is greater than or equal to 0.3mm, wherein the first distance is the distance between two adjacent auxiliary grid segments along the first direction, and the second distance is the distance between two adjacent first insulating parts along the first direction, thereby ensuring that the shape of the welding part after solidification is better, avoiding problems such as displacement, splitting or incomplete shape of the solder after solidification, ensuring better welding reliability, and thus ensuring better overall stability of the photovoltaic module.

[0052] The above-mentioned back contact battery of the present application will be specifically described below in combination with specific embodiments and comparative examples.

[0053] Example 1

[0054] This embodiment provides a back contact battery, comprising:

[0055] Battery body 1;

[0056] A plurality of first sub-grids 2 and a plurality of second sub-grids 3 are located on the battery body 1, the first sub-grids 2 and the second sub-grids 3 extend along a first direction x and are alternately arranged along a second direction y, the first sub-grids 2 and the second sub-grids 3 have different polarities, the first direction x intersects with the second direction y, the first sub-grids 2 and the second sub-grids 3 each include a plurality of sub-grid segments 4 arranged along the first direction x, and the distance between two adjacent sub-grid segments 4 along the first direction x is a first distance a;

[0057] A plurality of first insulating portions 5 are located on a side of the plurality of auxiliary grid segments 4 away from the battery body 1 and are arranged at intervals along the first direction x. The projection of the end of the auxiliary grid segment 4 on the battery body 1 is located in the projection of the first insulating portion 5 on the battery body 1. The distance between two adjacent first insulating portions 5 along the first direction x is a second distance c.

[0058] A plurality of welding portions 6 are located on a side of the auxiliary grid segment 4 away from the battery body 1 , and the welding portion 6 is located between two adjacent first insulating portions 5 along the first direction x;

[0059] The auxiliary gate segments 4 correspond to the first insulating portions 5 one by one, and the distance between two adjacent auxiliary gate segments 4 along the second direction y is the third distance s / 2, that is, the distance between two auxiliary gate segments with different polarities is the third distance s / 2, and the distance between the edge of the first insulating portion 5 and the corresponding auxiliary gate segment 4 is the fourth distance h / 2;

[0060] The difference between the first distance a and the second distance c is 0.3 cm, the difference between the second distance c and the width b of the welding portion 6 in the first direction x is 0.3 mm, and the difference between the third distance s / 2 and the fourth distance h / 2 is 0.15 mm.

[0061] Example 2

[0062] This embodiment provides a back-contact battery, the only difference between the back-contact battery and the embodiment 1 is that the difference between the first distance a and the second distance c is 0.5 cm, and the difference between the second distance c and the width b of the welding portion 6 in the first direction x is 0.6 mm.

[0063] Example 3

[0064] This embodiment provides a back-contact battery. The only difference between this back-contact battery and Embodiment 1 is that the difference between the third distance s / 2 and the fourth distance h / 2 is 0.3 mm.

[0065] Comparative Example 1

[0066] This embodiment provides a back-contact battery, the only difference between the back-contact battery and the embodiment 1 is that the difference between the first distance a and the second distance c is 0.6 cm, and the difference between the second distance c and the width b of the welding portion 6 in the first direction x is 0.1 mm.

[0067] Comparative Example 2

[0068] This embodiment provides a back-contact battery. The only difference between the back-contact battery and the embodiment 1 is that the difference between the first distance a and the second distance c is 0.2 cm, and the difference between the second distance c and the width b of the welding portion 6 in the first direction x is 0.16 mm.

[0069] Comparative Example 3

[0070] This embodiment provides a back-contact battery. The only difference between this back-contact battery and Embodiment 1 is that the difference between the third distance s / 2 and the fourth distance h / 2 is 0.09 mm.

[0071] The welding effect of the back contact cells in the above-mentioned embodiment 1, embodiment 2 and comparative example 1 was tested, and the test results are shown in Table 1:

[0072] Table 1

[0073]

[0074]

[0075] From the above experimental data, it can be seen that the welding effect of the welding part in Examples 1 to 3 is significantly better than the welding effect in Comparative Examples 1 to 2, indicating that the welding reliability of the back-contact battery of the present application is better; the curing effect of the first insulating part in Examples 1 to 3 is significantly better than the curing effect in Comparative Example 3, indicating that the insulation reliability of the back-contact battery of the present application is better.

[0076] For example, the welding effect diagram corresponding to Comparative Example 1 is as follows: Figure 3 As shown in FIG. 1 , it can be seen that the welded portion after solidification has an incomplete shape. The welding effect diagram corresponding to Comparative Example 2 is shown in FIG. Figure 4 As shown, it can be seen that the welded part after solidification has a split problem; the welding effect diagram corresponding to Example 1 is shown in Figure 5 As shown, the welding effect diagram corresponding to Example 2 is as follows Figure 6 As shown, it can be seen that the welded parts of Examples 1 and 2 after solidification do not have problems such as deviation, splitting or incomplete shape after solidification, and the welding effect is good.

[0077] The welding effect test was conducted on 1,000 back-contact batteries produced using the screen design size of the present application, and it was determined that the abnormal ratio of the welding effect of the welded part after curing was 0%, indicating that the present application has a significant effect on optimizing the welding reliability of the welded part after curing.

[0078] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0079] 1) In the back-contact battery of the present application, the dimensional relationship between the auxiliary grid line segment, the first insulating part and the welding part is quantified in the screen design, and the difference between the first distance and the second distance is limited to be greater than or equal to 0.3 mm, and the difference between the second distance and the width of the welding part in the first direction is greater than or equal to 0.3 mm, wherein the first distance is the distance between two adjacent auxiliary grid segments along the first direction, and the second distance is the distance between two adjacent first insulating parts along the first direction, thereby ensuring that the shape of the welding part after solidification is better, avoiding problems such as displacement, splitting or incomplete shape of the solder after solidification, and ensuring better welding reliability.

[0080] 2) The back-contact cell in the photovoltaic module of the present application quantifies the size relationship between the auxiliary grid line segment, the first insulating part and the welding part, limits the difference between the first distance and the second distance to be greater than or equal to 0.3 mm, and the difference between the second distance and the width of the welding part in the first direction is greater than or equal to 0.3 mm, wherein the first distance is the distance between two adjacent auxiliary grid segments along the first direction, and the second distance is the distance between two adjacent first insulating parts along the first direction, thereby ensuring that the shape of the welding part after solidification is better, avoiding problems such as displacement, splitting or incomplete shape of the solder after solidification, ensuring better welding reliability, and thus ensuring better overall stability of the photovoltaic module.

[0081] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0082] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A back contact battery, characterized in that: include: Battery body; A plurality of first sub-grids and a plurality of second sub-grids are located on the battery body, the first sub-grids and the second sub-grids extend along a first direction and are alternately arranged along a second direction, the first sub-grids and the second sub-grids have different polarities, the first direction intersects with the second direction, the first sub-grid and the second sub-grid each include a plurality of sub-grid segments arranged along the first direction, and the distance between two adjacent sub-grid segments along the first direction is a first distance; A plurality of first insulating parts are located on a side of the plurality of auxiliary grid segments away from the battery body, and are arranged at intervals along the first direction, the projection of the end of the auxiliary grid segment on the battery body is located in the projection of the first insulating part on the battery body, and the distance between two adjacent first insulating parts along the first direction is a second distance; A plurality of welding parts, located at a side of the auxiliary grid section away from the battery body, the welding part being located between two first insulating parts adjacent to each other along the first direction; A difference between the first distance and the second distance is greater than or equal to 0.3 mm, and a difference between the second distance and a width of the welding portion in the first direction is greater than or equal to 0.3 mm.

2. The back contact cell according to claim 1, characterized in that: The auxiliary gate segments correspond one-to-one to the first insulating parts, the distance between two adjacent auxiliary gate segments along the second direction is the third distance, the distance between the edge of the first insulating part and the corresponding auxiliary gate segment is the fourth distance, and the difference between the third distance and the fourth distance is greater than or equal to 0.15 mm.

3. The back contact battery according to claim 1, characterized in that: The first insulating portion is symmetrical about the secondary gate segment axis.

4. The back contact cell according to claim 1, characterized in that: The width of the first insulating portion in the second direction is 0.2-0.6 mm.

5. The back contact cell according to any one of claims 1 to 4, characterized in that The back contact battery further comprises: A plurality of main grids extend along the second direction and are arranged at intervals along the first direction. The main grid is located between two adjacent auxiliary grid segments along the first direction. The welding portion covers a portion of the main grid.

6. The back contact cell according to claim 5, characterized in that: The polarity of the main grid is the same as the polarity of the first auxiliary grid, the auxiliary grid segment of the second auxiliary grid is a second auxiliary grid segment, and the back contact battery further includes: A plurality of second insulating parts extend along the first direction and are arranged at intervals along the second direction, the auxiliary grid segment, the second insulating part and the main grid are arranged in a direction away from the battery body, the projections of the ends of two adjacent second auxiliary grid segments along the first direction on the battery body are located within the projections of the second insulating part on the battery body, and the projection of the main grid on the battery body overlaps with the projection of the second insulating part on the battery body.

7. The back contact cell according to claim 6, characterized in that: The plurality of second insulating parts include a plurality of edge insulating parts and a plurality of non-edge insulating parts, and a minimum distance between the edge insulating part and a surface edge of the battery body is smaller than a minimum distance between the non-edge insulating part and the surface edge.

8. The back contact battery according to claim 7, characterized in that: The widths of the edge insulating portion, the non-edge insulating portion, and the first insulating portion in the first direction increase sequentially.

9. The back contact cell according to claim 7, characterized in that: The width of the edge insulating portion in the first direction is 3 to 20 mm, and the width of the non-edge insulating portion in the first direction is 2 to 20 mm.

10. A photovoltaic module, characterized in that: include: A back contact cell as claimed in any one of claims 1 to 9.

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