Back contact solar cells and photovoltaic modules

Abstract

The present invention provides a back-contact solar cell and photovoltaic module, relating to the field of photovoltaic technology. The battery includes: 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 adjacent first doped regions and second doped regions is c; the electrode structure includes: an edge first electrode disk, a first collector grid line, a second collector grid line, and an edge first bus grid line; the second collector grid line includes: an edge second collector grid line close to the first side and close to the edge first electrode disk; in the second direction, the distance between the first electrode disk and the adjacent edge first bus grid line is H; in the first direction, the size of the edge first electrode disk is K; H ≥ 2 mm and K / 2 > (a + c), and the edge second collector grid line includes: a first section continuous with the main body and extending along the first direction. In this application, the gain of the carrier collection effect is greater, thereby improving the performance of the battery.

Description

TECHNICAL FIELD

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

[0002] The back contact solar cell can make full use of sunlight due to its structure without grid lines on the light side, so that it has higher efficiency, and due to the structure without grid lines on the light side, the appearance of the module end is more beautiful, so it has broad application prospects.

[0003] The edge position of the back contact solar cell is relatively special due to the position, and the edge first electrode disc and the edge first bus bar of the same polarity adjacent to the edge are usually spaced apart. However, in the above-mentioned back contact solar cell, the carrier collection effect is poor, which affects the performance of the back contact solar cell. SUMMARY

[0004] The present application provides a back contact solar cell and a photovoltaic module, which aims to solve the problem of poor carrier collection effect in the existing back contact solar cell.

[0005] In a first aspect of the present application, a back contact solar cell is provided, comprising: a cell body and an electrode structure located on the back side of the cell body;

[0006] The cell body comprises: a first edge on the back light side of the cell body, the first edge having a portion extending in a first direction; a first doped region and a second doped region spaced apart and having opposite doping types; 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 adjacent first doped regions and second doped regions is c;

[0007] The electrode structure comprises: an edge first electrode disc, a first current collecting grid line, a second current collecting grid line and an edge first bus bar; the edge first bus bar is located between the first edge and the edge first electrode disc; the edge first bus bar extends in the first direction; the first current collecting grid line and the second current collecting grid line both extend in a second direction and are alternately distributed in the first direction; the first current collecting grid line is arranged on the first doped region, and the second current collecting grid line is arranged on the second doped region; the first direction is different from the second direction; the second current collecting grid line comprises: an edge second current collecting grid line close to the first edge and close to the edge first electrode disc;

[0008] In the second direction, the distance between the edge first electrode disc and the edge first bus bar adjacent thereto is H;

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

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

[0011] In the present application, the edge second current collecting grid line comprises at least one bending part continuous with the main body part thereof; the bending part comprises: a first section extending along the first direction, and the above-mentioned bending part and first section realize the collection of carriers corresponding to the second current collecting grid line in the area between the edge first bus grid line and the edge first electrode disc, improve the carrier collection effect, and can improve the performance of the back contact solar cell. In addition, H<2mm, which means that the distance between the edge first electrode disc and the immediately adjacent edge first bus grid line in the second direction is small, and K / 2≤(a+c), which means that the size of the edge first electrode disc in the first direction is small, and the number of second current collecting grid lines broken in the first direction is also small. On the one hand, in the above two cases, even if the bending part is not set, the collection effect of the carriers to be collected by the second current collecting grid line is not greatly affected, and if the bending part is set, the cost of setting the bending part may be greater than the benefit brought by the carriers collected by the bending part. On the other hand, in the above two cases, the distance between the edge first electrode disc and the immediately adjacent edge first bus grid line is small, and the process difficulty of setting the bending part is large and the short circuit risk caused by setting the bending part is large. Therefore, in the present application, the edge second current collecting grid line is provided with the above-mentioned bending part only in the case of H≥2mm and K / 2>(a+c), that is, the present application improves the collection effect of the carriers to be collected by the second current collecting grid line on the basis of at least fully considering the setting cost of the bending part, the setting process difficulty of the bending part, and the short circuit risk, and is at least the result of balanced optimization of cost, process difficulty, short circuit risk and carrier collection effect. In summary, in the present application, the bending part is set only in the case where the distance between the edge first electrode disc and the immediately adjacent edge first bus grid line is necessary to set the bending part on the basis of fully considering the setting cost of the bending part, the setting process difficulty of the bending part, and the short circuit risk, thereby avoiding the cost problem, the process difficulty and the short circuit problem caused by blindly setting the bending part. In the present application, the gain of the carrier collection effect is more, the carrier collection effect is improved, the setting difficulty of the bending part is low, and the short circuit risk in the back contact solar cell is low, thereby improving the performance of the back contact solar cell.

[0012] Optionally, 8mm>H>3mm, and (K-b)>1.6×(a+2c), the bending part further comprises: a second section located on the first section and extending along the second direction.

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

[0014] Optionally, the second segment extends towards the edge first busbar line.

[0015] Optionally, on the same bending part, 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 edge first busbar line and the first current collecting grid line electrically connected to the edge first electrode disc is provided with a third segment extending in the second direction at a position corresponding to the first segment.

[0017] The third segment has an insulating gap with the second segment and the first segment.

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

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

[0020] Optionally, the electrode structure further comprises a connecting grid line connecting the edge first electrode disc and the edge first busbar line adjacent thereto.

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

[0022] In the second direction, the fourth segment has an insulating gap with the adjacent edge second current collecting grid line.

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

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

[0025] In the second direction: the size of the region where the fourth segment in the first doped layer is located is e, and the size of the region where the first segment in the second doped layer is located is f;

[0026] In the second direction: the size of the region where the fourth segment in the first doped layer is located is e, and the size of the region where the first segment in the second doped layer is located 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] Optionally, d≤c.

[0032] Optionally, the fourth segment on one connecting gate line is symmetrically distributed; and / or, the first segment on one bending part is symmetrically distributed.

[0033] In the second aspect of the present application, a photovoltaic module is provided, comprising: a plurality of any of the back contact solar cells described above.

[0034] The back contact solar cell and the photovoltaic module have the same or similar beneficial effects, and for the sake of brevity, the same will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments of the present application will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0036] Figure 1 、 Figure 2 , Figures 4 to 8 The partial structure schematic diagrams of several back contact solar cells in the embodiments of the present application are shown;

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

[0038] Brief Description of the Drawings

[0039] 1 - first doped region, 2 - second doped region, 3 - edge first electrode pad, 4 - first collector busbar, 5 - edge second collector busbar, 51 - main part, 52 - bending part, 521 - first section, 522 - second section, 6 - edge first busbar, 7 - third section, 8 - connecting busbar, 81 - fourth section. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0041] The present application provides a back contact solar cell, Figure 3 is Figure 2 A schematic diagram of an electrode structure in the back contact solar cell. The following refers to Figures 1 to 8 introduce the back contact solar cell provided by the present application.

[0042] Referring to Figures 1 to 8 , the back contact solar cell comprises a cell body (not marked in the figure) and an electrode structure located at the back side of the cell body, the electrode structure is used for collecting and conducting current. The cell body contains a PN junction, which can separate carriers. In the process of normal operation of the back contact solar cell, the side of the cell body mainly receiving light is the light receiving side, and the back light side is opposite to the light receiving side.

[0043] The cell body comprises a first edge (not marked in the figure) of the back light surface of the cell body, Figures 1 to 8In the embodiment, L1 represents a first direction, L2 represents a second direction, and the first side has a portion extending along the first direction L1. In the case where the first side is a straight line, the first side extends along the first direction L1, or in the case where the first side is a combination of a straight line and a broken line or a curve, the straight line portion of the first side extends along the first direction L1. The battery body further comprises: a first doped region 1 and a second doped region 2 arranged at intervals, and in the first direction L1: the size of the first doped region 1 is a, the size of the second doped region 2 is b, and the distance between adjacent first doped regions 1 and second doped regions 2 is c. Here, a is the width of the first doped region 1, b is the width of the second doped region 2, and c is the width of the interval between adjacent first doped regions 1 and second doped regions 2. Here, one of the first doped region 1 and the second doped region 2 is an N-type doped region, and the other is a P-type doped region. For example, the first doped region 1 is a P-type doped region, and the second doped region 2 is an N-type doped region. The electrode structure comprises: an edge first electrode disc 3, a first current collecting grid line 4, a second current collecting 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 disc 3. The edge first bus grid line 6 extends along the first direction L1, which means that in the case where 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 in the case where the edge first bus grid line 6 is a combination of a straight line, a curve, and a broken line, the straight line segment of the edge first bus grid line 6 extends along the first direction L1. The first current collecting grid line 4 and the second current collecting 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, one first current collecting grid line 4 is followed by one second current collecting grid line, which is followed by one first current collecting grid line 4. The first current collecting grid line 4 is arranged on the first doped region 1, and the second current collecting grid line is arranged on the second doped 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 current collecting grid line 4 collects carriers in the first doped region 1, and the second current collecting grid line collects carriers in the second doped region 2, thereby achieving current collection.

[0045] The second current collecting grid line comprises: an edge second current collecting grid line 5 close to the first side in the second direction L2 and close to the edge first electrode disc 3 in the first direction L1.

[0046] In the second direction L2, the distance between the edge first electrode disc 3 and the edge first bus grid line 6 adjacent thereto is H, and the direction of H can be parallel to the second direction L2. Here, H can be: the distance between the end point of the edge first electrode disc 3 adjacent to the first bus grid line 6 and the end point of the edge first bus grid line 6 adjacent to the edge first electrode disc 3 in the second direction L2; or, with reference to Figure 1, the distance between the geometric center of the edge first electrode disc 3 and the geometric center of the edge first busbar 6 in the second direction L2; or, the distance between the end point of the edge first electrode disc 3 closest to the edge first busbar 6 and the geometric center of the edge first busbar 6 in the second direction L2; or, the distance between the geometric center of the edge first electrode disc 3 and the end point of the edge first busbar 6 closest to the edge first electrode disc 3 in the second direction L2.

[0047] It should be noted that the edge first electrode disc is arranged in the region of the first doped layer where the edge first electrode disc is located, and the edge first busbar is arranged in the region of the first doped layer where the edge first busbar is located.

[0048] In the first direction L1, the size of the edge first electrode disc 3 is K; referring to Figure 1 , K can be the size of the edge first electrode disc 3 itself in the first direction L1. It should be noted that in the case where the sizes of the edge first electrode disc 3 at different positions in the first direction L1 are equal, K here can be the size of the edge first electrode disc 3 at any position in the first direction L1; in the case where the sizes of the edge first electrode disc 3 at different positions in the first direction L1 are not equal, K here can be the maximum size of the edge first electrode disc in the first direction. H≥2mm and K / 2>(a+c), the edge second current collecting grid line 5 comprises: a main body part 51 extending along the second direction L2 and adjacent to the edge first electrode disc 3 in the first direction L1, and at least one bending part 52 continuous with the main body part 51; the bending part 52 comprises: a first segment 521 continuous with the main body part 51 and extending along the first direction L1. Referring to Figure 1 and 2 , both of the edge second current collecting grid lines 5 contain a main body part 51 and a bending part 52 continuous with the main body part 51, and each bending part 52 comprises: a first segment 521 continuous with the main body part 51 and extending along the first direction L1. Meanwhile, referring to Figure 2 , the two edge second current collecting 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 current collecting grid line 5 comprises at least one bending part 52 continuous with the main body part 51 thereof; the bending part 52 comprises a first section 521 extending along the first direction L1, and the bending part 52 and the first section 521 realize the collection of the carriers corresponding to the second current collecting grid line in the area between the edge first bus grid line 6 and the edge first electrode disc 3, improve the carrier collection effect, and can improve the performance of the back contact solar cell. In addition, H < 2mm, which means that the distance between the edge first electrode disc 3 and the adjacent edge first bus grid line 6 in the second direction L2 is small, and K / 2 ≤ (a+c), which means that the size of the edge first electrode disc 3 in the first direction L1 is small, and the number of the second current collecting grid lines broken in the first direction L1 is also small. On the one hand, in the above two cases, even if the bending part is not set, the collection effect of the carriers to be collected by the second current collecting grid line is not greatly affected, and if the bending part is set, the cost of setting the bending part will be greater than the benefit brought by the carriers collected by the bending part. On the other hand, in the above two cases, the distance between the edge first electrode disc 3 and the adjacent edge first bus grid line 6 is small, and the process difficulty of setting the bending part is large and the short circuit risk caused by setting the bending part is large. Therefore, in the present application, only when H ≥ 2mm and K / 2 > (a+c), the edge second current collecting grid line 5 is provided with the above-mentioned bending part 52, that is, the present application improves the collection effect of the carriers to be collected by the second current collecting grid line on the basis of at least considering the setting cost of the bending part 52, the setting process difficulty of the bending part 52 and the short circuit risk, and is at least the result of the balanced optimization of the cost, the process difficulty, the short circuit risk and the carrier collection effect. In summary, the present application improves the carrier collection effect and the performance of the back contact solar cell on the basis of fully considering the setting cost of the bending part 52, the setting process difficulty of the bending part 52 and the short circuit risk.

[0050] Optionally, referring to Figures 1 to 3 , and Figure 7, 8mm > H > 3mm, and (K-b) > 1.6 x (a+2c), the bending part 52 can further include: a second section 522 located on the first section 521 and extending along the second direction L2. 8mm > H > 3mm indicates that the distance between the edge first electrode disc 3 and the adjacent edge first bus bar line 6 is large, and there are more carriers in the space corresponding to the second current collecting grid line, so it is necessary to collect, otherwise the collection effect of the carriers will be greatly affected; (K-b) ≤ 1.6 x (a+2c) indicates that the size of the edge first electrode disc 3 in the first direction L1 is small, the number of second current collecting grid lines broken in the first direction L1 is also small, and in the first direction L1, it may not be able to accommodate the next second section 522, and even if it can accommodate the next second section 522, not only the setting difficulty is large, but also the short circuit risk is high; (K-b) > 1.6 x (a+2c) indicates that the size of the edge first electrode disc 3 in the first direction L1 is large, the number of second current collecting grid lines broken in the first direction L1 is also 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 risk; therefore, in the present application, 8mm > H > 3mm, and (K-b) > 1.6 x (a+2c), the bending part 52 can further include: a second section 522 located on the first section 521 and extending along the second direction L2, which is based on the necessity of setting the second section 522, and ensures that the second section 522 is easy to set, and the short circuit risk is small, and the collection effect of the carriers is improved.

[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 (K-b) = 1.7 x (a+2c), (K-b) = 1.9 x (a+2c), (K-b) = 2 x (a+2c), (K-b) = 2.1 x (a+2c), (K-b) = 2.2 x (a+2c), (K-b) = 2.5 x (a+2c), (K-b) = 3 x (a+2c), (K-b) = 3.2 x (a+2c), (K-b) = 3.5 x (a+2c), (K-b) = 4 x (a+2c), the bending part 52 can further include: a second section 522 located on the first section 521 and extending along the second direction L2.

[0052] It should be noted that the number of first sections 521 and second sections 522 in the bending part 52, and their respective sizes, are specific to the specific sizes of H and K, and the setting cost is greater than the carrier gain, and the setting process difficulty is low, and there is no short circuit risk.

[0053] Optionally, the second segment 522 can be co-linear with the second current collecting grid line located on the side of the edge first electrode disc 3 away from the edge first bus grid line 6, so that the second segment 522 can be set at one time when the second current collecting grid line is set, and the process is more convenient.

[0054] Optionally, referring to Figures 1 to 7 , at least one of the edge first bus grid line 6 and the first current collecting grid line electrically connected to the edge first electrode disc 3, a third segment 7 extending along the second direction L2 is arranged at the position corresponding to the first segment 521; the third segment 7 has an insulating gap with the second segment 522 and the first segment 521, so as to avoid short circuit; in the aforementioned first direction L1, the second segment 522 and the third segment 7 are alternately distributed, that is, in the first direction L1, one second segment 522, followed by one third segment 7, and then one second segment 522; the second segment 522 is co-linear with the second current collecting grid line located on the side of the edge first electrode disc 3 away from the edge first bus grid line 6, so that the second segment 522 can be set at one time when the second current collecting grid line is set, and the process is more convenient; the third segment 7 is co-linear with the first current collecting grid line at the corresponding position, so that the third segment 7 can be set at one time when the first current collecting grid line is set, and the process is more convenient.

[0055] It should be noted that the first current collecting grid line electrically connected to the edge first electrode disc 3 can include: Figure 3 the first current collecting grid line directly electrically connected to the edge first electrode disc 3, or can include: Figure 6 the first current collecting grid line indirectly electrically connected to the edge first electrode disc 3. It can be Figure 1 , only the edge first bus grid line 6, at the position corresponding to the first segment 521, a third segment 7 extending along the second direction L2 is arranged, or Figure 2 , only the first current collecting grid line electrically connected to the edge first electrode disc, at the position corresponding to the first segment 521, a third segment 7 extending along the second direction L2 is arranged, or the edge first bus grid line 6 and the first current collecting grid line electrically connected to the edge first electrode disc, at the position corresponding to the first segment 521, a third segment 7 extending along the second direction L2 is arranged, which is not specifically limited. The number of the third segment 7 is determined according to the setting cost, carrier gain, short circuit risk, etc.

[0056] Optionally, referring to Figures 4 to 6, 10mm > H ≥ 8mm and (K-2b) > 1.6×(a+2c), the same bending part 52, the number of the second section 522 is greater than or equal to 2. 10mm > H ≥ 8mm and (K-2b) > 1.6×(a+2c) indicates that the size between the edge first electrode disc 3 and the adjacent edge first busbar line 6 is large, and the size of the edge first electrode disc 3 in the first direction L1 is large, and the number of the second current collecting grid line broken in the first direction L1 is also large, which has a greater impact on the collection effect of the carriers corresponding to the second current collecting grid line. At the same time, in the first direction L1, at least two second sections 522 can be accommodated, and the setting difficulty is small, and short circuit is not caused. Therefore, in the present application, 10mm > H ≥ 8mm and (K-2b) > 1.6×(a+2c), the number of the second section 522 located on the first section 521 and extending along the second direction L2 in the bending part 52 is greater than or equal to 2, which ensures that the second section 522 is easy to set and has small risk of short circuit, and improves the collection effect of the carriers.

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

[0058] It should be noted that, 10mm > H ≥ 8mm and (K-2b) > 1.6×(a+2c), the same bending part 52, the number of the second section 522, and the size, are specifically determined according to the specific size of H and K, and the setting cost is greater than the carrier gain, and the setting process difficulty is low, and short circuit is not caused.

[0059] Optionally, referring to Figure 1 and Figure 7, the second section 522 extends towards the edge first busbar 6. Specifically, the current or carrier on the second section 522 needs to be collected on the main body 51 of the edge second collecting grid line 5 first, and then collected to the second busbar (not shown in the figure) electrically connected with the edge second collecting grid line 5 to realize collection and conduction. At the same time, the second busbar electrically connected with the edge second collecting grid line 5 is arranged on the side of the edge first electrode disc 3 away from the edge first busbar 6, so that the second section 522 extends towards the edge first busbar 6, and the current or carrier on the second section 522 is always collected on the main body 51 of the edge second collecting grid line 5 in the direction close to the second busbar electrically connected with the edge second collecting grid line 5, and the current or carrier on the second section 522 does not move in the direction away from the second busbar electrically connected with the edge second collecting grid line 5, so that the transmission distance of the current or carrier on the second section 522 is shorter, and the collection and conduction efficiency of the carrier or current is higher.

[0060] For example, Figure 2 , the current or carrier on the second section 522 moves in the direction away from the second busbar electrically connected with the edge second collecting grid line 5 first, and then moves in the direction close to the second busbar electrically connected with the edge second collecting grid line 5, which obviously increases the transmission distance of the current or carrier, causes transmission loss and recombination, and thus Figure 2 , the collection and conduction efficiency of the current or carrier is lower than that in the case of Figure 1 .

[0061] Optionally, referring to Figures 1 to 7 , the number of the second sections 522 on the same bending part 52 is greater than or equal to the number of the first sections 521. Specifically, the extension direction of the second section 522 is the same as the extension direction of the main body 51 of the edge second collecting grid line 5, and the second section 522 can be arranged at the same time as the main body 51 of the second collecting grid line 5 is arranged, without additional process, so that the arrangement process of the second section 522 is simpler, and thus, in the case of containing the first section 521 and the second section 522 at the same time on the same bending part 52, the number of the second sections 522 is greater, which can simplify the arrangement process of the edge second collecting grid line and reduce the arrangement cost, and the second section 522 can also achieve good carrier collection effect.

[0062] Optionally, referring to Figure 8, H≥10mm and K / 2>(a+c), the bending part 52 only includes the first section 521, and the number of the first section 521 in the same bending part 52 is greater than or equal to 2. Specifically, first, H≥10mm and K / 2>(a+c) indicate that the distance between the edge first electrode disc 3 and the adjacent edge first busbar 6 is large, the size of the edge first electrode disc 3 in the first direction L1 is large, the number of the second current collecting grid line interrupted in the first direction L1 is also large, and the current collector gain brought by the setting of the bending part 52 is larger compared with the cost of setting the bending part 52, and the setting process of the bending part 52 is relatively low and basically does not bring new short circuit risk; second, H≥10mm indicates that the distance between the edge first electrode disc and the adjacent edge first busbar is too large, and due to the current or carrier on the bending part 52, the current or carrier needs to be collected to the main part 51 of the edge second current collecting grid line 5 first, and then collected to the second busbar (not shown in the figure) electrically connected with the edge second current collecting grid line 5 to realize collection and conduction. At the same time, the second busbar electrically connected with the edge second current collecting grid line 5 is arranged on the side of the edge first electrode disc 3 away from the edge first busbar 6, and due to the too large H, the transmission distance of the current or carrier on the main part 51 is relatively long, so in the present application, the bending part 52 only includes the first section 521, and except for the first section 521 closest to the edge first busbar 6, the remaining first sections 521 are closer to the second busbar electrically connected with the edge second current collecting grid line 5, that is, the transmission distance of the current or carrier on the remaining first sections 521 is shorter, thereby improving the collection and conduction efficiency of the current or carrier. More specifically, under the condition of H≥10mm and K / 2>(a+c), if the second section 522 is also arranged on the bending part 52, since the second section 522 extends along the second direction L2, the transmission distance of the current or carrier on substantially all the second sections 522 is longer, which will bring certain transmission loss and recombination, so the bending part 52 only includes the first section 521, the transmission distance of the current or carrier on the first section 521 is shorter, the transmission loss is smaller, and the collection and conduction efficiency of the current or carrier is improved. The specific number of the first section 521 in one bending part 52 is not limited, and is determined by factors such as setting cost, setting difficulty, short circuit risk, and carrier gain.

[0063] For example, Figure 8 In the above embodiment, the number of the first section 521 in the same bending part 52 is 3. For example, the number of the first section 521 in the same bending part 52 can also be 2, 4, 5, etc. Natural numbers are determined by factors such as setting cost, carrier collection gain, and short circuit risk.

[0064] Optionally, referring to Figure 8The electrode structure further comprises: a connecting bus line 8 connecting the edge first electrode disc 3 and the adjacent edge first bus line 6; the fourth segment 81 extending in the first direction L1 is arranged on the connecting bus 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, one first segment 521, then one fourth segment 81, and then one first segment 521 are distributed, so that the current or carrier can be uniformly collected and conducted; in the second direction L2, the fourth segment 81 and the adjacent edge second bus line 5 have an insulating gap, that is, the fourth segment 81 and the main body part 51 and the bending part 52 of the adjacent edge second bus line 5 have an insulating gap, so as to avoid short circuit.

[0065] Optionally, referring to Figure 8 The fourth segment 81 and the fourth segment 81 on one connecting bus line 8 are symmetrically distributed, and the collection of the carrier is more uniform, wherein the axis of symmetry is parallel to the first direction and parallel to the second direction. Figure 8 Optionally, referring to Figure 8 The first segment 521 and the first segment 521 on one bending part 52 are symmetrically distributed, and the collection of the carrier is more uniform, wherein the axis of symmetry is parallel to the first direction.

[0066] Optionally, the battery body further comprises: a first doped layer and a second doped layer having opposite doping types; the first doped region is a part of the first doped layer, and the second doped region is a part of the second doped layer; the first doped layer is one of an N-type doped layer and a P-type doped layer, and the second doped layer is the other of the N-type doped layer and the P-type doped layer. The fourth segment 81 is located on the first doped layer, and the first segment 521 is located on the second doped layer; in the second direction L2, the interval size between the region in the first doped layer where the fourth segment 81 is located and the region in the second doped layer where the first segment 521 adjacent to the fourth segment 81 is located is d, referring to Figure 8Here, d can be the shortest distance between 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 doped layer is located is e, the size of the region where the first segment 521 in the second doped layer is located is f, the number of the first segment 521 between the edge first electrode pad 3 and the edge first busbar 6 connected by one connection gate line 8 is m, and the number of the fourth segment 81 is x, where x and m are natural numbers; then (x+m+2)d+(m+1)f+(x+1)e>H≥(x+m+1)d+mf+xe. That is, 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 the m first segments 521 is mf, and the total size of the x fourth segments 81 is xe; H is enough to set m first segments 521, x fourth segments 81, and an interval 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 is a risk of short circuit, or the setting process is difficult, therefore, by determining m and x by the above inequality, there is basically no risk of short circuit, and the setting process is less difficult and the setting cost is lower.

[0067] For example, Figure 8 In the above embodiment, the number of first segments 521 in one bending part 52 is m=3, and two fourth segments 81 are arranged on one connection gate line 8, that is, x=2. Here, m can also be 2, 4, 5, etc., and x can be 1, 3, 4, etc.

[0068] It should be noted that the determination method of d, e, and f here is the same as the determination method of a described above.

[0069] Optionally, m>x, specifically, the collection effect of the current carriers corresponding to the edge second busbar 5 between the edge first electrode pad 3 and the edge first busbar 6 is not good enough, therefore, as many first segments 521 as possible are arranged to further improve the collection effect of the current carriers corresponding to the edge second busbar 5 and improve the performance of the back contact solar cell.

[0070] Optionally, referring to Figure 8 m=x+1, not only more first segments 521 are arranged, but also as many fourth segments 81 as possible are arranged, which is better for the collection of two kinds of current carriers and improves the performance of the back contact solar cell. For example, Figure 8 In the above embodiment, m=3 and x=2, and other arrangement modes are not limited.

[0071] Optionally, e≤a, f≤b, specifically, the first collecting grid line needs to be provided with the connecting grid line 8, and the main body 51 of the edge second collecting grid line 5 also needs to be provided with each first segment 521, therefore, the width a of the first doped area corresponding to the first collecting grid line is larger, facilitating the setting of the connecting grid line, and the width b of the second doped area corresponding to the second collecting grid line is larger, also facilitating the setting of more bending parts.

[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 grid line 8, specifically, the connecting grid line 8 needs to collect the current collected by each fourth segment 81, and the main body 51 of the edge second collecting grid line 5 also needs to collect the current collected by each first segment 521. Therefore, in the case that 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 grid line 8, it is more conducive to the collection of current; in the case that 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 grid 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 interval size between the region where the fourth segment 81 is located in the first doped layer and the region where the first segment 521 adjacent to the fourth segment 81 is located in the second doped layer is d, and the distance between the adjacent first doped area and the second doped area is c; d≤c. Specifically, d

[0074] In the present application, due to the foregoing improvement, since the edge first electrode disc 3 is farther away from the first side than the edge first busbar 6, the proportion of hidden cracks caused by welding is reduced by about 1.6% compared with the case where the edge first electrode disc 3 is arranged on the edge first busbar 6. Through the foregoing improvement, the collection ability of the edge photogenerated carriers is strengthened, the recombination loss in the carrier transport process is reduced, and the like, thereby improving the battery efficiency.

[0075] It should be noted that, for the purpose of clarity and conciseness of description, the following description mainly refers to the structure of the edge first electrode disc 3, and the edge first busbar 6 is not mentioned. Figures 1 to 8The above description of the present application is in detail for the case of one first edge in the back contact solar cell. In the case of a back contact solar cell including a plurality of first edges, the case of each first edge is similar to the case of the first edge, and can be referred to each other, and in order to avoid repetition, it will not be described here. For example, the shape of the back contact solar cell is approximately rectangular, and has two first edges oppositely distributed along the second direction L2, then, the polarity of the edge first busbar line adjacent to one first edge along the second direction L2 and the polarity of the edge first busbar line adjacent to the other first edge along the second direction L2 can be different or the same, and this is not specifically limited. For example, the edge first busbar line adjacent to one first edge along the second direction L2 is an edge N-type busbar line, and the edge first busbar line adjacent to the other first edge along the second direction L2 is an edge P-type busbar line. For another example, the edge first busbar line adjacent to one first edge along the second direction L2 is an edge N-type busbar line, and the edge first busbar line adjacent to the other first edge along the second direction L2 is also an edge N-type busbar line. For another example, the edge first busbar line adjacent to one first edge along the second direction L2 is an edge P-type busbar line, and the edge first busbar line adjacent to the other first edge along the second direction L2 is also an edge P-type busbar line. In the above several cases, the edge first busbar line adjacent to each first edge, and the corresponding edge first electrode disc, edge second busbar line, etc. all conform to the foregoing related description.

[0076] The present application can also provide a photovoltaic module, which can include a plurality of any one of the foregoing back contact solar cells, and the photovoltaic module can further include encapsulation adhesive films, etc. on the light side and the back side of the back contact solar cells, and the specific structure of the photovoltaic module is not limited.

[0077] It should be noted that the photovoltaic module and any one of the foregoing back contact solar cells are related, and can be referred to each other, and have the same or similar beneficial effects, and in order to avoid repetition, it will not be described here.

[0078] It should be noted that in this document, the terms "comprise", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitation, the element defined by the statement "comprises a" does not exclude the existence of another same element in the process, method, article or device including the element.

[0079] The embodiments of the present application are described above with reference to the accompanying drawings, but the present application is not limited to the above-described specific embodiments, and the above-described specific embodiments are merely illustrative, but not restrictive, and a person of ordinary skill in the art can make many forms under the inspiration of the present application without departing from the purpose of the present application and the scope protected by the claims, and these all belong to the protection of the present application.

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 includes: a first side located on a 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 spaced apart and having opposite doping types; in the first direction: a size of the first doping region is a, a size of the second doping region is b, and a distance c between adjacent first doping regions and second doping regions; The electrode structure includes: 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 doped region, and the second collector grid line is arranged on the second doped region; the first direction is different from the second direction; the second collector grid line includes: 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 plate 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 bent portion continuous with the main body; the bent 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, wherein: 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.

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 segments 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 bus bar 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 segments is greater than or equal to the number of the first segments.

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 are insulating gaps 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 the second collector grid line located on the side of the edge first electrode disk away from the edge first bus grid line, and the third segment is collinear with the first collector grid line at the corresponding position.

7. The back contact solar cell according to claim 1, wherein: 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 exists 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 of the first doping layer, and the second doping region is a partial region of 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 between the region where the fourth segment is located in the first doped layer and the region where the first segment adjacent to the fourth segment is located in the second doped layer is d; between the edge first electrode pad and the edge first bus bar connected by one connecting grid line, 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 section thereon are symmetrically distributed; and / or one of the bending portions and the first section thereon are symmetrically distributed.

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

Images