Back contact solar cell and photovoltaic module

Abstract

The invention provides a back contact solar cell and a photovoltaic module, and relates to the technical field of photovoltaics. The battery comprises a battery body and an electrode structure, in the first direction, the size of the first doped region is a, the size of the second doped region is b, and the distance between the adjacent first doped region and second doped region is c; the electrode structure comprises an edge first electrode disc, a first current collection grid line, a second current collection grid line and an edge first bus grid line; the second current collection grid line comprises an edge second current collection grid line which is close to the first edge and close to the edge first electrode disc; in the second direction, the distance between the first electrode disc and the adjacent edge first bus grid line is H; in the first direction, the size of the edge first electrode disc is K; h > = 2mm and K / 2 > (a + c). The edge second collector grid line includes a first segment continuous with the main body portion and extending along the first direction. According to the invention, the gain of the collection effect of current carriers is higher, and the performance of the cell is improved.

Description

Technical Field

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

[0002] Back-contact solar cells can make full use of sunlight due to their structure without grid lines on the light-facing side, making them more efficient. In addition, due to their structure without grid lines on the light-facing side, the appearance of the component end is more beautiful, so they have broad application prospects.

[0003] The edge of the back contact solar cell is located in a special position, and the edge first electrode disk and edge first busbar line of the same polarity adjacent to the edge are usually arranged at intervals. However, in the above back contact solar cell, the carrier collection effect is poor, which affects the performance of the back contact solar cell. Summary of the invention

[0004] The present invention provides a back-contact solar cell and a photovoltaic module, aiming to solve the problem of poor carrier collection effect in existing back-contact solar cells.

[0005] A first aspect of the present invention provides a back-contact solar cell, comprising: a cell body and an electrode structure located on the back side of the cell body;

[0006] The battery body comprises: a first side located on the backlight surface of the battery body, the first side having a portion extending along a first direction; a first doping region and a second doping region arranged at intervals and having opposite doping types; in the first direction: the size of the first doping region is a, the size of the second doping region is b, and the distance between adjacent first doping regions and second doping regions is c;

[0007] The electrode structure comprises: an edge first electrode disk, a first collector grid line, a second collector grid line and an edge first bus grid line; the edge first bus grid line is located between the first edge and the edge first electrode disk; the edge first bus grid line extends along the first direction; the first collector grid line and the second collector grid line both extend along the second direction and are alternately distributed along the first direction; the first collector grid line is arranged on the first doping region, and the second collector grid line is arranged on the second doping region; the first direction is different from the second direction; the second collector grid line comprises: an edge second collector grid line close to the first edge and close to the edge first electrode disk;

[0008] In the second direction, the distance between the edge first electrode disk and the adjacent edge first busbar line is H;

[0009] In the first direction, the size of the edge first electrode disk is K;

[0010] H≥2mm and K / 2>(a+c), the edge second collector grid line includes: a main body extending along the second direction and adjacent to the edge first electrode disk in the first direction, and at least one bending portion continuous with the main body; the bending portion includes: a first section continuous with the main body and extending along the first direction.

[0011] In the present application, the edge second collector grid line includes at least one bend portion continuous with its main body; the bend portion includes: a first section extending along the first direction, the bend portion and the first section realize the collection of carriers corresponding to the second collector grid line in the area between the edge first bus grid line and the edge first electrode disk, improve the carrier collection effect, and can improve the performance of the back contact solar cell. In addition, H < 2mm, indicating that the distance between the edge first electrode disk and the adjacent edge first bus grid line in the second direction is small, K / 2 ≤ (a + c), indicating that the size of the edge first electrode disk in the first direction is small, and the number of the second collector grid lines interrupted in the first direction is also small. On the one hand, in the above two cases, even if the bend portion is not set, the collection effect of the carriers to be collected by the second collector grid line is not greatly affected. If the bend portion is set, the increased cost of setting the bend portion may be greater than the benefit brought by the carriers collected by the bend portion; on the other hand, in the above two cases, The distance between the edge first electrode disk and the adjacent edge first collector grid line is small, the process difficulty of setting the bending portion is large and the short-circuit risk caused by setting the bending portion is large; therefore, in this application, the above-mentioned bending portion is set in the edge second collector grid line only when H≥2mm and K / 2>(a+c). That is to say, this application improves the collection effect of the carriers to be collected by the second collector grid line on the basis of at least fully considering the setting cost of the bending portion, the setting process difficulty of the bending portion, and the short-circuit risk. It is at least the result of balanced optimization of cost, process difficulty, short-circuit risk and carrier collection effect. To sum up, the present application sets a bending portion only when the distance between the edge first electrode disk and the adjacent edge first bus bar line requires setting a bending portion, based on full consideration of the setting cost of the bending portion, the setting process difficulty of the bending portion, and the short-circuit risk. This avoids the cost problems, process difficulties and short-circuit problems caused by blindly setting the bending portion. In the present application, the gain of the carrier collection effect is greater, the carrier collection effect is improved, and the setting difficulty of the bending portion is lower, and the short-circuit risk in the back-contact solar cell is lower, thereby improving the performance of the back-contact solar cell.

[0012] Optionally, 8mm>H>3mm, and (Kb)>1.6×(a+2c), the bending portion further includes: a second segment located on the first segment and extending along the second direction.

[0013] Optionally, 10mm>H≥8mm and (K-2b)>1.6×(a+2c), and the number of the second sections on the same bending portion is greater than or equal to 2.

[0014] Optionally, the second section extends toward the edge first busbar line.

[0015] Optionally, on the same bending portion, the number of the second segments is greater than or equal to the number of the first segments.

[0016] Optionally, at least one of the first edge busbar line and the first collector grid line electrically connected to the first edge electrode plate is provided with a third section extending along the second direction at a position corresponding to the first section;

[0017] There is an insulating gap between the third section, the second section and the first section;

[0018] In the first direction, the second segment and the third segment are alternately distributed, and the second segment is collinear with a second collector grid line located on a side of the edge first electrode disk away from the edge first bus grid line, and the third segment is collinear with a first collector grid line at a corresponding position.

[0019] Optionally, H≥10 mm, the bending portion only includes the first segment, and the number of the first segments in the same bending portion is greater than or equal to 2.

[0020] Optionally, the electrode structure further comprises: a connecting grid line connecting the edge first electrode plate and the adjacent edge first bus grid line;

[0021] The connecting grid line is provided with a fourth segment extending along the first direction; in the second direction, the fourth segment and the first segment are spaced and alternately distributed;

[0022] In the second direction, an insulating gap is provided between the fourth segment and the adjacent edge second collector grid line.

[0023] Optionally, the battery body further includes: a first doping layer and a second doping layer with opposite doping types; the first doping region is a partial region in the first doping layer, and the second doping region is a partial region in the second doping layer;

[0024] The fourth segment is located on the first doped layer, and the first segment is located on the second doped layer;

[0025] Along the second direction: the spacing dimension between the region where the fourth segment is located in the first doping layer and the region where the first segment adjacent to the fourth segment is located in the second doping layer is d, and between the edge first electrode plate and the edge first busbar connected by one of the connecting grid lines, the number of the first segments is m, and the number of the fourth segments is x;

[0026] In the second direction: the size of the region where the fourth segment is located in the first doped layer is e, and the size of the region where the first segment is located in the second doped layer is f;

[0027] (x+m+2)d+(m+1)f+(x+1)e>H≥(x+m+1)d+mf+xe.

[0028] Optionally, m>x.

[0029] Optionally, m=(x+1).

[0030] Optionally, e≤a, f≤b; and / or, the line width of the first segment is less than or equal to the line width of the main body, and the line width of the fourth segment is less than or equal to the line width of the connecting gate line.

[0031] Optional, d≤c.

[0032] Optionally, one of the connecting grid lines and the fourth segment thereon are symmetrically distributed; and / or one of the bending portions and the first segment thereon.

[0033] A second aspect of the present invention provides a photovoltaic module, comprising: a plurality of any of the aforementioned back-contact solar cells.

[0034] The above-mentioned back-contact solar cells and photovoltaic modules have the same or similar beneficial effects, which will not be described again here to avoid repetition. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0036] Figure 1 , Figure 2 , Figures 4 to 8 Schematic diagrams of partial structures of several back-contact solar cells in embodiments of the present invention are shown;

[0037] Figure 3A schematic diagram of the partial structure of an electrode structure in a back-contact solar cell according to an embodiment of the present invention is shown.

[0038] Description of the accompanying drawings:

[0039] 1-first doping region, 2-second doping region, 3-edge first electrode disk, 4-first collector grid line, 5-edge second collector grid line, 51-main body, 52-bending portion, 521-first section, 522-second section, 6-edge first collector grid line, 7-third section, 8-connecting grid line, 81-fourth section. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] The present invention provides a back contact solar cell. Figure 3 yes Figure 2 Schematic diagram of the electrode structure in FIG. Figures 1 to 8 The back contact solar cell provided in this application is introduced.

[0042] Reference Figures 1 to 8 , a back-contact solar cell includes: a cell body (not marked in the figure) and an electrode structure located on the back side of the cell body, the electrode structure is used to collect and conduct current. The cell body contains a PN junction that can separate carriers. During the normal operation of the back-contact solar cell, the side of the cell body that mainly receives light is the light-facing side, and the backlight side is opposite to the light-facing side.

[0043] The battery body comprises: a first side (not marked in the figure) located on the backlight surface of the battery body, Figures 1 to 8In the figure, L1 indicates the first direction, L2 indicates the second direction, and the first side has a portion extending along the first direction L1. When the first side is a straight line, the first side extends along the first direction L1, or when the first side is a combination of a straight line, a fold line, and a curve, the straight portion of the first side extends along the first direction L1. The battery body also includes: a first doping region 1 and a second doping region 2 arranged at intervals, in the first direction L1: the size of the first doping region 1 is a, the size of the second doping region 2 is b, and the distance between adjacent first doping regions 1 and second doping regions 2 is c. Here, a is the width of the first doping region 1, b is the width of the second doping region 2, and c is the width of the interval between adjacent first doping regions 1 and second doping regions 2. Here, one of the first doping region 1 and the second doping region 2 is an N-type doping region, and the other is a P-type doping region. For example, the first doping region 1 is a P-type doping region, and the second doping region 2 is an N-type doping region. The electrode structure includes: an edge first electrode disk 3, a first collector grid line 4, a second collector grid line and an edge first bus grid line 6; the first side is located on the left side of the edge first bus grid line 6, and the edge first bus grid line 6 is located between the first side and the edge first electrode disk 3. The edge first bus grid line 6 extends along the first direction L1, which means that when the edge first bus grid line 6 is a straight line, the edge first bus grid line 6 extends along the first direction L1, and when the edge first bus grid line 6 is a combination of a straight line, a curve, and a broken line, the straight line segment in the edge first bus grid line 6 extends along the first direction L1. The first collector grid line 4 and the second collector grid line both extend along the second direction L2, and are alternately distributed along the first direction L1, that is, in the first direction L1, a first collector grid line 4 is followed by a second collector grid line, and then by a first collector grid line 4. The first collector gate line 4 is arranged on the first doping region 1, and the second collector gate line is arranged on the second doping region 2; the first direction L1 is different from the second direction L2, and the angle between the first direction L1 and the second direction L2 is not specifically limited, for example, they can be perpendicular to each other.

[0044] The first collector gate line 4 collects carriers in the first doping region 1 , and the second collector gate line collects carriers in the second doping region 2 , thereby realizing current collection.

[0045] The second collector grid lines include: edge second collector grid lines 5 close to the first side in the second direction L2 and close to the edge first electrode plate 3 in the first direction L1.

[0046] In the second direction L2, the distance between the edge first electrode disk 3 and the adjacent edge first busbar line 6 is H, and the direction of H may be parallel to the second direction L2. Here, H may be: the distance between the end point of the edge first electrode disk 3 adjacent to the first busbar line 6 and the end point of the edge first busbar line 6 adjacent to the edge first electrode disk 3 in the second direction L2; or, referring to Figure 1, the distance between the geometric center of the first edge electrode disk 3 and the geometric center of the first edge bus line 6 in the second direction L2; or, the distance between the endpoint of the first edge electrode disk 3 adjacent to the first bus line 6 and the geometric center of the first edge bus line 6 in the second direction L2; or, the distance between the geometric center of the first edge electrode disk 3 and the endpoint of the first edge bus line 6 adjacent to the first edge electrode disk 3 in the second direction L2.

[0047] It should be noted that the edge first electrode disk is arranged in the region where the edge first electrode disk is located in the first doping layer, and the edge first bus bar line is arranged in the region where the edge first bus bar line is located in the first doping layer.

[0048] In the first direction L1, the size of the edge first electrode disk 3 is K; Figure 1 , K can be the size of the edge first electrode disk 3 itself in the first direction L1. It should be noted that, when the sizes of different positions of the edge first electrode disk 3 in the first direction L1 are equal, K here can be the size of any position of the edge first electrode disk 3 in the first direction L1; when the sizes of different positions of the edge first electrode disk 3 in the first direction L1 are not equal, K here can be the maximum size of the edge first electrode disk in the first direction. H≥2mm and K / 2>(a+c), the edge second collector grid line 5 includes: a main body 51 extending along the second direction L2 and adjacent to the edge first electrode disk 3 in the first direction L1, and at least one bending portion 52 continuous with the main body 51; the bending portion 52 includes: a first section 521 continuous with the main body 51 and extending along the first direction L1. Refer to Figure 1 and 2 The two edge second collector grid lines 5 each include a main body 51 and a bent portion 52 continuous with the main body 51, and each bent portion 52 includes: a first segment 521 continuous with the main body 51 and extending along the first direction L1. Figure 2 The two edge second collector grid lines 5 are symmetrically distributed, and the symmetry axis is parallel to the second direction L2.

[0049] In the present application, the edge second collector grid line 5 includes at least one bend 52 continuous with its main body 51; the bend 52 includes: a first section 521 extending along the first direction L1, the bend 52 and the first section 521 realize the collection of carriers corresponding to the second collector grid line in the area between the edge first bus grid line 6 and the edge first electrode disk 3, improve the carrier collection effect, and improve the performance of the back contact solar cell. In addition, H < 2mm, indicating that the distance between the edge first electrode disk 3 and the adjacent edge first bus grid line 6 in the second direction L2 is small, K / 2 ≤ (a + c), indicating that the size of the edge first electrode disk 3 in the first direction L1 is small, and the number of the second collector grid lines interrupted in the first direction L1 is also small. On the one hand, in the above two cases, even if the bend is not set, the collection effect of the carriers to be collected by the second collector grid line is not greatly affected. If the bend is set, the cost of setting the bend will be greater than the benefit brought by the carriers collected by the bend; on the other hand, in the above two cases, the edge The distance between the edge first electrode disk 3 and the adjacent edge first collector grid line 6 is small, the process difficulty of setting the bend portion is large, and the risk of short circuit caused by setting the bend portion is large; therefore, in this application, the above-mentioned bend portion 52 is set on the edge second collector grid line 5 only when H≥2mm and K / 2>(a+c), that is to say, this application improves the collection effect of the carriers to be collected by the second collector grid line on the basis of at least fully considering the setting cost of the bend portion 52, the setting process difficulty of the bend portion 52, and the risk of short circuit, which is at least the result of balanced optimization of cost, process difficulty, short circuit risk and carrier collection effect. In summary, this application improves the carrier collection effect and improves the performance of the back contact solar cell on the basis of fully considering the setting cost of the bend portion 52, the setting process difficulty of the bend portion 52, and the risk of short circuit.

[0050] Optional, see Figures 1 to 3 ,as well as Figure 7, 8mm>H>3mm, and (Kb)>1.6×(a+2c), the bending portion 52 may also include: a second segment 522 located on the first segment 521 and extending along the second direction L2. 8mm>H>3mm, indicating that the distance between the edge first electrode disk 3 and the adjacent edge first collector grid line 6 is large, and there are many carriers corresponding to the second collector grid lines in this space, and it is very necessary to collect them, otherwise the collection effect of the carriers will be greatly affected; (Kb)≤1.6×(a+2c), indicating that the size of the edge first electrode disk 3 in the first direction L1 is small, and the number of the second collector grid lines interrupted in the first direction L1 is also small, and in the first direction L1, it may not be possible to accommodate the next second segment 522, and even if it can accommodate the next one The second section 522 is not only difficult to set up but also has a high risk of short circuit; (Kb)>1.6×(a+2c), which means that the size of the edge first electrode disk 3 in the first direction L1 is relatively large, and the number of second collector grid lines interrupted in the first direction L1 is also relatively large, and in the first direction L1, at least one second section 522 can be accommodated, and the setting difficulty is small, and there is no short circuit; therefore, in the present application, 8mm>H>3mm, and (Kb)>1.6×(a+2c), the bending portion 52 can also include: a second section 522 located on the first section 521 and extending along the second direction L2, which is based on the need to set the second section 522, ensuring that the second section 522 is easy to set, has a low risk of short circuit, and improves the carrier collection effect.

[0051] For example, when H is 3.1mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 7.9mm, and (Kb)=1.7×(a+2c), (Kb)=1.9×(a+2c), (Kb)=2×(a+2c), (Kb)=2.1×(a+2c), (Kb)=2.2×(a+2c), (Kb)=2.5×(a+2c), (Kb)=3×(a+2c), (Kb)=3.2×(a+2c), (Kb)=3.5×(a+2c), (Kb)=4×(a+2c), the bending portion 52 may further include: a second segment 522 located on the first segment 521 and extending along the second direction L2.

[0052] It should be noted that the number of the first section 521 and the second section 522 in the bending portion 52, as well as their respective sizes, are determined based on the specific sizes of H and K, and the setting cost is greater than the carrier gain. At the same time, the setting process difficulty is low and it will not cause a short circuit.

[0053] Optionally, the second section 522 here can be colinear with the second collector grid line located on the side of the edge first electrode disk 3 away from the edge first bus grid line 6, so that the second section 522 can be set at the same time as the second collector grid line is set, which is more convenient.

[0054] Optional, see Figures 1 to 7 In at least one of the first edge bus grid line 6 and the first collector grid line electrically connected to the first edge electrode disk 3, a third section 7 extending along the second direction L2 is arranged at a position corresponding to the first section 521; there is an insulating gap between the third section 7 and the second section 522 and the first section 521 to avoid short circuit; in the aforementioned first direction L1, the second section 522 and the third section 7 are alternately distributed, that is, in the first direction L1, a second section 522 is followed by a third section 7, and then a second section 522; and the second section 522 is collinear with the second collector grid line located on the side of the first edge electrode disk 3 away from the first edge bus grid line 6, so that the second section 522 can be set at one time when the second collector grid line is set, and the process is more convenient, and the third section 7 is collinear with the first collector grid line corresponding to the position, so that the third section 7 can be set at one time when the first collector grid line is set, and the process is more convenient.

[0055] It should be noted that the first collector grid line electrically connected to the edge first electrode disk 3 may include: Figure 3 The first collector grid line directly electrically connected to the edge first electrode disk 3 may also include: Figure 6 The first collector grid line is electrically connected to the first electrode plate 3 at the edge. Figure 1 In the embodiment, only the edge first busbar line 6 is provided with a third segment 7 extending along the second direction L2 at a position corresponding to the first segment 521, or it may be Figure 2 In the embodiment, only the first collector grid line electrically connected to the first electrode disk at the edge is provided with a third segment 7 extending along the second direction L2 at a position corresponding to the first segment 521, or the first collector grid line at the edge 6 and the first collector grid line electrically connected to the first electrode disk at the edge are provided with a third segment 7 extending along the second direction L2 at a position corresponding to the first segment 521, and no specific limitation is made to this. The number of the third segments 7 here is determined by the setting cost, carrier gain, short circuit risk, etc.

[0056] Optional, see Figures 4 to 6, 10mm>H≥8mm and (K-2b)>1.6×(a+2c), on the same bending portion 52, the number of second segments 522 is greater than or equal to 2. 10mm>H≥8mm and (K-2b)>1.6×(a+2c), indicating that the size between the edge first electrode disk 3 and the adjacent edge first collector grid line 6 is larger, and the size of the edge first electrode disk 3 in the first direction L1 is larger, and the number of the second collector grid lines interrupted in the first direction L1 is also larger, which has a greater collection effect on the carriers corresponding to the second collector grid lines. The impact is relatively large. At the same time, in the first direction L1, at least two second sections 522 can be accommodated, and the setting is easy and will not cause short circuit; therefore, in this application, 10mm>H≥8mm and (K-2b)>1.6×(a+2c), the number of second sections 522 located on the first section 521 and extending along the second direction L2 in the bending portion 52 is greater than or equal to 2. It is necessary to set the second section 522, which ensures that the second section 522 is easy to set, has a small risk of short circuit, and improves the carrier collection effect.

[0057] For example, Figures 4 to 6 , 10mm>H≥8mm and (K-2b)>1.6×(a+2c), the number of the second segments 522 on the same bending portion 52 is 2. For another example, 10mm>H≥8mm and (K-2b)>1.6×(a+2c), the number of the second segments 522 on the same bending portion 52 can also be a natural number such as 3, 4, or 5.

[0058] It should be noted that, 10mm>H≥8mm and (K-2b)>1.6×(a+2c), the number and size of the second sections 522 on the same bending portion 52 are determined based on the specific sizes of H and K, and the setting cost is greater than the carrier gain. At the same time, the setting process difficulty is low and it will not cause a short circuit.

[0059] Optional, see Figure 1 and Figure 7, the second section 522 extends toward the edge first bus grid line 6. Specifically, the current or carriers on the second section 522 need to be first collected on the main body 51 of the edge second collector grid line 5, and then collected on the second bus grid line (not shown in the figure) electrically connected to the edge second collector grid line 5 to achieve collection and conduction. At the same time, the second bus grid line electrically connected to the edge second collector grid line 5 is set on the side of the edge first electrode disk 3 away from the edge first bus grid line 6. Therefore, the second section 522 extends toward the edge first bus grid line 6, and the current or carriers on the second section 522 are always collected on the main body 51 of the edge second collector grid line 5 along the direction close to the second bus grid line electrically connected to the edge second collector grid line 5. The current or carriers on the second section 522 do not move in the direction away from the second bus grid line electrically connected to the edge second collector grid line 5. Therefore, the transmission distance of the current or carriers on the second section 522 is shorter, and the collection and conduction efficiency of the carriers or current is higher.

[0060] For example, Figure 2 In the embodiment, the current or carriers on the second section 522 first move in a direction away from the second bus grid line electrically connected to the second collector grid line 5 at the edge, and then move in a direction close to the second bus grid line electrically connected to the second collector grid line 5 at the edge after being collected on the main body 51. The current or carriers on the second section 522 first move in a direction away from the second bus grid line electrically connected to the second collector grid line 5 at the edge, which significantly increases the transmission distance of the current or carriers, and may cause transmission loss and recombination, so Figure 2 The collection and conduction efficiency of medium current or carriers is not as good as Figure 1 The collection and conduction efficiency of medium current or carriers.

[0061] Optional, see Figures 1 to 7 , on the same bending portion 52, the number of the second segments 522 is greater than or equal to the number of the first segments 521. Specifically, the extension direction of the second segments 522 is the same as the extension direction of the main body 51 of the edge second collector grid line 5, and the second segments 522 can be set at the same time as the main body 51 of the second collector grid line 5, without the need for additional processes, so the setting process of the second segments 522 is simpler. Therefore, in the case where the first segments 521 and the second segments 522 are contained on the same bending portion 52, the number of the second segments 522 is greater, which can simplify the setting process of the edge second collector grid line and reduce its setting cost, and the second segments 522 can also achieve a good carrier collection effect.

[0062] Optional, see Figure 8, H≥10 mm and K / 2>(a+c), the bending portion 52 only includes the first section 521, and the number of the first sections 521 in the same bending portion 52 is greater than or equal to 2. Specifically, first, H≥10mm and K / 2>(a+c), indicating that the distance between the edge first electrode disk 3 and the adjacent edge first collector grid line 6 is large, and the size of the edge first electrode disk 3 in the first direction L1 is large, and the number of the second collector grid lines interrupted in the first direction L1 is also large. Compared with the cost of setting the bending portion 52, the carrier collection gain brought by setting the bending portion 52 is greater, and the setting process difficulty of the bending portion 52 is relatively low, and basically no new short circuit risk is brought; secondly, H≥10mm, indicating that the distance between the edge first electrode disk and the adjacent edge first collector grid line is too large, and the current or carriers on the bending portion 52 need to be first collected on the main body 51 of the edge second collector grid line 5, and then collected on the second collector grid line (not shown in the figure) electrically connected to the edge second collector grid line 5 to achieve collection and conduction. At the same time, the second bus grid line electrically connected to the edge second collector grid line 5 is arranged on the side of the edge first electrode disk 3 away from the edge first bus grid line 6. Since H is too large, the current or carrier transmission distance on the main body 51 is longer. Therefore, in the present application, the bent portion 52 only includes the first section 521. Except for the first section 521 closest to the edge first bus grid line 6, the remaining first sections 521 are closer to the second bus grid line electrically connected to the edge second collector grid line 5. In other words, the transmission distance of the current or carrier on the remaining first sections 521 is shorter, thereby improving the collection and conduction efficiency of carriers or current. More specifically, when H≥10mm and K / 2>(a+c), if a second section 522 is also provided on the bending portion 52, since the second section 522 extends along the second direction L2, the transmission distance of the current or carriers on substantially all the second sections 522 is longer, which will bring about certain transmission loss and recombination, so the bending portion 52 only includes the first section 521, and the transmission distance of the current or carriers on the first section 521 is shorter, the transmission loss is smaller, and the collection and conduction efficiency of the carriers or current is improved. The specific number of the first sections 521 in a bending portion 52 is not limited, and is determined by factors such as its setting cost, setting difficulty, short circuit risk, and carrier gain.

[0063] For example, Figure 8 In the embodiment, the number of the first sections 521 in the same bending portion 52 is 3. For another example, the number of the first sections 521 in the same bending portion 52 can also be a natural number such as 2, 4, or 5, which is specifically determined based on the setting cost, the carrier collection gain, the short circuit risk, and other factors.

[0064] Optional, see Figure 8The electrode structure also includes: a connecting grid line 8 connecting the edge first electrode disk 3 and the adjacent edge first collector grid line 6; a fourth segment 81 extending along the first direction L1 is arranged on the connecting grid line 8; in the second direction L2, the fourth segment 81 and the first segment 521 are spaced and alternately distributed, that is, in the second direction L2, a first segment 521 is followed by a fourth segment 81, and then a first segment 521 is distributed in this way, which can uniformly collect and conduct current or carriers; in the second direction L2, an insulating gap is provided between the fourth segment 81 and the adjacent edge second collector grid line 5, that is, an insulating gap is provided between the fourth segment 81 and the main body 51 and the bending portion 52 of the adjacent edge second collector grid line 5 to avoid short circuit.

[0065] Optional, see Figure 8 , a connecting gate line 8 and the fourth segment 81 thereon are symmetrically distributed, and the carrier collection is relatively uniform, and the symmetry axis here is parallel to the first direction and also parallel to the second direction; optionally, refer to Figure 8 A bending portion 52 and a first section 521 thereon are symmetrically distributed, and the symmetry axis here is parallel to the first direction, so the collection of carriers is more uniform.

[0066] Optionally, the battery body further includes: a first doping layer and a second doping layer of opposite doping types; the first doping region is a partial region in the first doping layer, and the second doping region is a partial region in the second doping layer; the first doping layer here is one of an N-type doping layer and a P-type doping layer, and the second doping layer is the other of an N-type doping layer and a P-type doping layer. The fourth segment 81 is located on the first doping layer, and the first segment 521 is located on the second doping layer; along the second direction L2: the interval size between the region where the fourth segment 81 is located in the first doping layer and the region where the first segment 521 adjacent to the fourth segment 81 is located in the second doping layer is d, refer to Figure 8, where d can be the shortest distance between the two regions in the second direction L2. In the second direction L2: the size of the region where the fourth segment 81 in the first doping layer is located is e, the size of the region where the first segment 521 in the second doping layer is f, between the edge first electrode disk 3 and the edge first busbar line 6 connected by a connecting grid line 8, the number of first segments 521 is m, and the number of fourth segments 81 is x, where x and m are both natural numbers; then (x+m+2)d+(m+1)f+(x+1)e>H≥(x+m+1)d+mf+xe. That is to say, in the second direction L2: the total number of intervals between the first segment 521 and the second segment 81 is x+m+1, the total size of these intervals is (x+m+1)d, the total size of m first segments 521 is mf, and the total size of x fourth segments 81 is xe, then H is enough to set m first segments 521, x fourth segments 81, and there are intervals between adjacent first segments 521 and second segments 81, but H is not enough to set one more first segment 521 and one more fourth segment 81, otherwise there will be a risk of short circuit, or the setting process will be very difficult. Therefore, m and x determined by the above inequality basically have no short circuit risk, and the setting process is less difficult and the setting cost is lower.

[0067] For example, Figure 8 In the embodiment, the number m of the first segments 521 in a bending portion 52 is 3, and two fourth segments 81 are provided on a connecting grid line 8, that is, x is 2. Here, m can also be a natural number such as 2, 4, 5, and x can be a natural number such as 1, 3, 4, etc.

[0068] It should be noted that the method for determining d, e, and f here is the same as the method for determining a mentioned above.

[0069] Optionally, m>x. Specifically, between the edge first electrode disk 3 and the edge first collector grid line 6, the collection effect of carriers corresponding to the edge second collector grid line 5 is poor. Therefore, setting as many first sections 521 as possible can further enhance the collection effect of carriers corresponding to the edge second collector grid line 5 and improve the performance of the back contact solar cell.

[0070] Optional, see Figure 8 , m=x+1, which not only ensures that more first segments 521 are set, but also sets as many fourth segments 81 as possible, which has a better collection effect on both types of carriers and improves the performance of the back contact solar cell. For example, Figure 8 In the example, m=3, x=2, and no limitation is imposed on other configurations.

[0071] Optionally, e≤a, f≤b. Specifically, a connecting gate line 8 needs to be set on the first collecting gate line, and each first segment 521 also needs to be set on the main body 51 of the edge second collecting gate line 5. Therefore, the width a of the first doped region corresponding to the first collecting gate line is larger, which is convenient for setting the connecting gate line, and the width b of the second doped region corresponding to the second collecting gate line is larger, which is also convenient for setting more bending portions.

[0072] Optionally, the line width of the first segment 521 is less than or equal to the line width of the main body 51, and the line width of the fourth segment 81 is less than or equal to the line width of the connecting gate line 8. Specifically, the connecting gate line 8 needs to collect the current collected by each fourth segment 81 thereon, and the main body 51 of the edge second collector gate line 5 also needs to collect the current collected by each first segment 521. Therefore, in the case where the line width of the first segment 521 is less than the line width of the main body 51, and the line width of the fourth segment 81 is less than the line width of the connecting gate line 8, it is more conducive to the collection of current; in the case where the line width of the first segment 521 is equal to the line width of the main body 51, and the line width of the fourth segment 81 is equal to the line width of the connecting gate line 8, since the corresponding line widths are equal, the setting process is simpler and the setting cost can be reduced.

[0073] Optionally, along the second direction L2: the spacing dimension between the region where the fourth segment 81 in the first doping layer is located and the region where the first segment 521 adjacent to the fourth segment 81 in the second doping layer is located is d, and the distance between the adjacent first doping region and the second doping region is c; d≤c. Specifically, d<c, the current flowing through the first collector grid line and the second collector grid line may be larger, and the harm of the short circuit between the two may be greater, so c is larger to reduce the risk of short circuit as much as possible; d=c, then the size of the region corresponding to the insulation is equal, and the process parameters of the two are relatively compatible, which can reduce the process difficulty and reduce the setting cost.

[0074] In the present application, through the aforementioned improvements, since the edge first electrode disk 3 is farther away from the first side than the edge first busbar line 6, the proportion of hidden cracks caused by welding is reduced by about 1.6% compared with setting the edge first electrode disk 3 on the edge first busbar line 6. Through the aforementioned improvements, the ability to collect edge photogenerated carriers is enhanced, the recombination loss in the carrier transmission process is reduced, etc., thereby improving the battery efficiency.

[0075] It should be noted that, refer to Figures 1 to 8, the above content of the present application is a detailed description of the situation of a first side in a back contact solar cell. In the case where a back contact solar cell includes multiple first sides, the situation of each first side is similar to the situation of the first side, and can be referenced to each other. In order to avoid repetition, it will not be repeated here. For example, the shape of the back contact solar cell is roughly rectangular, and has two first sides relatively distributed along the second direction L2. Then, the edge first bus line adjacent to a first side along the second direction L2 and the edge first bus line adjacent to another first side along the second direction L2 may have different or the same polarity, and no specific limitation is made on this. For example, the edge first bus line adjacent to a first side along the second direction L2 is an edge N-type bus line, and the edge first bus line adjacent to another first side along the second direction L2 is an edge P-type bus line. For another example, the edge first bus line adjacent to a first side along the second direction L2 is an edge N-type bus line, and the edge first bus line adjacent to another first side along the second direction L2 is also an edge N-type bus line. For another example, the edge first bus grid line adjacent to a first side along the second direction L2 is an edge P-type bus grid line, and the edge first bus grid line adjacent to another first side along the second direction L2 is also an edge P-type bus grid line. In the above cases, the edge first bus grid lines adjacent to each first side, and the corresponding edge first electrode plates, edge second collector grid lines, etc., all comply with the above-mentioned relevant records.

[0076] The present application may also provide a photovoltaic module, which may include any one of the aforementioned back-contact solar cells. The photovoltaic module may also include: an encapsulation film located on the light-facing side and the backlight side of the back-contact solar cell, etc., and the specific structure of the photovoltaic module is not limited.

[0077] It should be noted that the photovoltaic module and any of the aforementioned back-contact solar cells can be referenced to each other in relation to each other and have the same or similar beneficial effects. In order to avoid repetition, they will not be described again here.

[0078] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article 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, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0079] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A back contact solar cell, characterized in that: include: A battery body and an electrode structure located on the back side of the battery body; The battery body comprises: a first side located on the backlight surface of the battery body, the first side having a portion extending along a first direction; a first doping region and a second doping region arranged at intervals and having opposite doping types; in the first direction: the size of the first doping region is a, the size of the second doping region is b, and the distance between adjacent first doping regions and second doping regions is c; The electrode structure comprises: an edge first electrode disk, a first collector grid line, a second collector grid line and an edge first bus grid line; the edge first bus grid line is located between the first edge and the edge first electrode disk; the edge first bus grid line extends along the first direction; the first collector grid line and the second collector grid line both extend along the second direction and are alternately distributed along the first direction; the first collector grid line is arranged on the first doping region, and the second collector grid line is arranged on the second doping region; the first direction is different from the second direction; the second collector grid line comprises: an edge second collector grid line close to the first edge and close to the edge first electrode disk; In the second direction, the distance between the edge first electrode disk and the adjacent edge first busbar line is H; In the first direction, the size of the edge first electrode disk is K; H≥2mm and K / 2>(a+c), the edge second collector grid line includes: a main body extending along the second direction and adjacent to the edge first electrode disk in the first direction, and at least one bending portion continuous with the main body; the bending portion includes: a first section continuous with the main body and extending along the first direction.

2. The back contact solar cell according to claim 1, characterized in that: 8mm>H>3mm, and (Kb)>1.6×(a+2c), the bending portion also includes: a second section located on the first section and extending along the second direction.

3. The back contact solar cell according to claim 2, characterized in that: 10mm>H≥8mm and (K-2b)>1.6×(a+2c), on the same bending portion, the number of the second sections is greater than or equal to 2.

4. The back contact solar cell according to claim 2 or 3, characterized in that: The second segment extends toward the edge first busbar line.

5. The back contact solar cell according to claim 2 or 3, characterized in that: On the same bending portion, the number of the second sections is greater than or equal to the number of the first sections.

6. The back contact solar cell according to claim 2 or 3, characterized in that: At least one of the first edge busbar line and the first collector grid line electrically connected to the first edge electrode plate is provided with a third section extending along the second direction at a position corresponding to the first section; There is an insulating gap between the third section, the second section and the first section; In the first direction, the second segment and the third segment are alternately distributed, and the second segment is collinear with a second collector grid line located on a side of the edge first electrode disk away from the edge first bus grid line, and the third segment is collinear with a first collector grid line at a corresponding position.

7. The back contact solar cell according to claim 1, characterized in that: H≥10mm, the bending portion only includes the first segment, and the number of the first segments in the same bending portion is greater than or equal to 2.

8. The back contact solar cell according to claim 7, characterized in that: The electrode structure further includes: a connecting grid line connecting the edge first electrode plate and the adjacent edge first bus grid line; The connecting grid line is provided with a fourth segment extending along the first direction; in the second direction, the fourth segment and the first segment are spaced and alternately distributed; In the second direction, an insulating gap is provided between the fourth segment and the adjacent edge second collector grid line.

9. The back contact solar cell according to claim 8, characterized in that: The battery body further includes: a first doping layer and a second doping layer with opposite doping types; the first doping region is a partial region in the first doping layer, and the second doping region is a partial region in the second doping layer; The fourth segment is located on the first doped layer, and the first segment is located on the second doped layer; Along the second direction: the spacing dimension between the region where the fourth segment is located in the first doping layer and the region where the first segment adjacent to the fourth segment is located in the second doping layer is d, and between the edge first electrode plate and the edge first busbar connected by one of the connecting grid lines, the number of the first segments is m, and the number of the fourth segments is x; In the second direction: the size of the region where the fourth segment is located in the first doped layer is e, and the size of the region where the first segment is located in the second doped layer is f; (x+m+2)d+(m+1)f+(x+1)e>H≥(x+m+1)d+mf+xe.

10. The back contact solar cell according to claim 9, characterized in that: m>x.

11. The back contact solar cell according to claim 9, characterized in that: m=(x+1).

12. The back contact solar cell according to claim 9, characterized in that: e≤a, f≤b; and / or, the line width of the first segment is smaller than or equal to the line width of the main body, and the line width of the fourth segment is smaller than or equal to the line width of the connecting gate line.

13. The back contact solar cell according to claim 9, characterized in that: d≤c.

14. The back-contact solar cell according to any one of claims 8 to 13, characterized in that: One of the connecting grid lines and the fourth segment thereon are symmetrically distributed; and / or, one of the bending portions and the first segment thereon.

15. A photovoltaic module, characterized in that: include: A back-contact solar cell as claimed in any one of claims 1 to 14.

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