Back contact battery and photovoltaic module

Abstract

The invention discloses a back contact battery and a photovoltaic module, and the back contact battery comprises a battery body which comprises a first surface and a second surface which are oppositely disposed; the first surface comprises a first area close to the first edge; the plurality of first fine grids and the plurality of second fine grids are arranged on the first surface, are alternately distributed along the first direction and extend along the second direction; the first end part conductive piece is arranged on the first area, extends along the first direction and is connected with the at least two first fine grids, and the second fine grids are interrupted at the first end part conductive piece; the at least one first end conductive member is provided with a first voltage test point. Therefore, in the IV or EL test process, the test probe adopted in the IV or EL test is electrically connected with the first voltage test point, and the first voltage test point can be stably contacted with the test probe, so that stable electric connection is formed between the test probe and the first voltage test point, the test difficulty is reduced, and the reliability and stability of the IV or EL test are improved.

Description

Technical Field

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

[0002] A back-contact cell refers to a solar cell in which the light-facing side of the cell has no electrode, and the positive and negative electrodes are arranged on the backlight side of the cell. This can reduce the shading of the electrode to the cell, increase the short-circuit current of the cell, and improve the energy conversion efficiency of the cell.

[0003] In order to reduce the use of slurry and reduce the risk of short circuit, some back-contact solar cells adopt a busbar-free design. However, on the one hand, in such a technical solution, due to the busbar-free design on the back side, the difficulty of performing IV, EL (Electro Luminescence) and other performance tests on the back-contact solar cells is greatly increased. The back-contact solar cells cannot have stable contact with the test probes, making the test more difficult and the reliability and stability poorer. Summary of the invention

[0004] The purpose of this application is to provide a back-contact cell and photovoltaic module to reduce the difficulty of testing and improve the reliability and stability of the test.

[0005] In order to achieve the above objectives, this application provides the following technical solutions:

[0006] A back contact battery, comprising:

[0007] The battery body comprises a first surface and a second surface arranged opposite to each other, wherein the first surface comprises a first side and a second side arranged opposite to each other along a first direction, and a third side and a fourth side arranged opposite to each other along a second direction; and the first surface further comprises a first area close to the first side;

[0008] A plurality of first fine grids and a plurality of second fine grids are arranged on the first surface, and are alternately distributed along the first direction and extend along the second direction, the first direction intersects the second direction, and the first fine grids and the second fine grids have different properties;

[0009] A first end conductive member is disposed on the first region and extends along the first direction and connects at least two first fine grids, and the second fine grid is interrupted at the first end conductive member;

[0010] At least one first end conductive member has a first voltage testing point.

[0011] In the back-contact battery provided in the present application, at least one first end conductive member has a first voltage test point. The first voltage test point can be any component that cooperates with the test probe or an area that cooperates with the test probe. For example, the first voltage test point can be an open voltage needle. In this way, during the IV or EL test process, the test probe used in the IV or EL test is electrically connected to the first voltage test point, and the first voltage test point and the test probe can be in stable contact, so that a stable electrical connection is formed between the test probe and the first voltage test point, thereby reducing the test difficulty and improving the reliability and stability of the IV or EL test.

[0012] In one implementation, the width of the first voltage test point along the second direction is greater than the width of the first end conductive member along the second direction. This configuration widens the width of the first voltage test point along the second direction, which is beneficial to providing a contact area between the first voltage test point and the test probe, and further ensures a stable electrical connection between the test probe and the first voltage test point.

[0013] In one implementation, the first voltage test point is set at the intersection of the first fine grid and the first end conductive member. With this technical solution, along the second direction, the first voltage test point is aligned with a first fine grid, and the current of the first fine grid can flow to the first voltage test point along the shortest distance, shortening the flow distance of the current, thereby reducing current loss and further improving the reliability and stability of the test.

[0014] In one implementation, the first end conductive member includes a first end away from the first edge;

[0015] The distance between the first voltage test point and the first end is S1, the length of the first end conductive part along the first direction is L1, and S1 / L1 is less than or equal to 0.5. This arrangement can prevent the first voltage test point from extending too long along the first direction, resulting in excessive transmission resistance of the first voltage test point, affecting the accuracy of the test. At the same time, during string soldering, even if the end of the electrical connector (solder strip) extends above the first voltage test point due to an error, the fine grid can be protected from being welded off, so the first voltage test point needs to be slightly closer to the first solder pad.

[0016] In one implementation, the first end conductive member includes a first end away from the first side; the back contact battery also includes a first pad disposed in the first region, the first pad is electrically connected to the first end of the first end conductive member, and the first pad is connected to at least one first fine grid. With such an arrangement, the current of the first fine grid connected to the first pad can flow directly to the first pad, ensuring that the current of the first fine grid connected to the first pad can flow to the first pad along the shortest distance, shortening the flow distance of the current, thereby reducing current loss, and further improving the reliability and stability of the test.

[0017] In one implementation, the first voltage test point and the first pad have the same width along the second direction. With this technical solution, the first voltage test point and the first pad can be aligned to ensure that the first fine grid aligned with the first voltage test point and the first fine grid connected to the first pad are equal in length, so that the current distribution is more uniform, thereby reducing current loss.

[0018] In one implementation, in the first region, the battery body includes a plurality of laminated parts, the plurality of laminated parts are arranged at intervals along the first direction, and the laminated parts include a first doping layer and a second doping layer arranged in a stacked manner, and the first voltage test point is arranged on one of the laminated parts. Since the height of the laminated parts is relatively high, the first voltage test point is arranged on the laminated parts, and it is easier to identify the first voltage test point during the test process, which is conducive to improving the test efficiency.

[0019] In one implementation, it further includes a second region away from the first region and adjacent to the first region, a plurality of second pads are disposed on the second region, the plurality of second pads are electrically connected to the first fine grid located in the second region, and are arranged at intervals along the first direction;

[0020] Along the second direction, the width of the first voltage test point, the width of the first pad and the width of the second pad are equal, so that the lengths of the first fine grid connected to the first voltage test point, the first fine grid connected to the first pad and the first fine grid connected to the second pad are equal, and the current distribution is more uniform, thereby reducing current loss.

[0021] And / or, along the first direction, the extension distance of the first voltage test point and the extension distance of the second pad are both smaller than the extension distance of the first pad. In this technical solution, by making the extension distance of the first pad along the first direction larger than the extension distance of the second pad and the first voltage test point along the first direction, the conductive volume of the first pad is increased, the transmission resistance of the first pad is reduced, and thus the current loss is reduced, and the power generation efficiency of the back contact battery is improved.

[0022] In one implementation, it also includes a second end conductive member disposed in the first region and extending along the first direction, the second end conductive member and the first end conductive member are alternately disposed in sequence along the second direction, at least one second end conductive member is disposed with a second voltage test point, and the second voltage test points on the adjacent second end conductive members and the first end conductive member are staggered with the first voltage test point along the first direction. With this technical solution, along the first direction, the first voltage test point can be aligned with the first fine grid, and the second voltage test point can be aligned with the second fine grid, so that the current in the first fine grid aligned with the first voltage test point and the second fine grid aligned with the second voltage test point can flow to the voltage test point through the shortest distance, further reducing the current loss.

[0023] In one implementation, the first area is equally divided into two parts along the second direction, and at least one first end conductive member and at least one second end conductive member in each part have a voltage test point; and / or,

[0024] The back side of the back contact battery includes two first areas and a second area between the two first areas. Any first area is evenly divided into two parts, and at least one first end conductive member and at least one second end conductive member in each part have voltage test points. With this technical solution, the first voltage test points and the second voltage test points are more evenly distributed in the first area, avoiding test errors caused by uneven areas and further improving the accuracy of back contact battery testing.

[0025] In one implementation, in the first end conductive member and the second end conductive member adjacent to each other along the second direction, the first voltage test point on the first end conductive member is electrically connected to a first fine grid, and the second voltage test point on the second end conductive member is electrically connected to a second fine grid, and the first fine grid electrically connected to the first voltage test point and the second fine grid electrically connected to the second voltage test point are arranged adjacent to each other along the first direction. With such an arrangement, the distance between the first voltage test point and the second voltage test point on the adjacent first end conductive member and the second end conductive member is smaller, and the accuracy of the test is higher.

[0026] In one implementation, along the first direction, the difference between the extension distances of the first end conductive member and the second end conductive member is equal to the spacing between adjacent first fine grids and second fine grids. This arrangement ensures that the first end conductive member and the second end conductive member are roughly aligned in the first direction, so that the currents flowing through the first end conductive member and the second end conductive member are roughly the same, avoiding the situation of excessive current and excessive temperature in the local area, and ensuring the stability of the performance of the entire back contact battery.

[0027] In one implementation, the first end conductive member is electrically connected to at least five first fine grids. When the electrical connector is electrically connected to the first end conductive member, the electrical connector does not need to extend to the vicinity of the first edge, and the distance between the end of the electrical connector and the first edge is large, thereby preventing the electrical connector extending to the vicinity of the first edge from shaking and misaligning, resulting in leakage.

[0028] In one implementation, along the direction close to the first side, the width of the first end conductive member along the second direction gradually decreases. It can be understood that the current flowing through the first end conductive member or the second end conductive member along the direction close to the second region gradually increases, so in this technical solution, the width of the first end conductive member or the second end conductive member gradually increases along the direction close to the second region, so that the transmission resistance of the first end conductive member or the second end conductive member gradually decreases, and the transmission resistance of the first end conductive member or the second end conductive member is adapted to the current inside it, further reducing the current loss, thereby improving the efficiency of the solar cell.

[0029] A photovoltaic component comprises a back contact cell as described in any one of the above items and an electrical connector, wherein the electrical connector is conductively connected to a plurality of first fine grids.

[0030] Compared with the prior art, the beneficial effects of the photovoltaic module provided in the present application are the same as the beneficial effects of the above-mentioned back-contact battery, which will not be elaborated here.

[0031] In one implementation, the first end conductive member includes a first end away from the first edge; the back contact battery also includes a first pad disposed in the first region, the first pad is electrically connected to the first end of the first end conductive member and is disposed near a boundary between the first region and the second region;

[0032] Along the first direction, the end of the electrical connector is located between the first pad and the first voltage test point. This arrangement can ensure that the electrical connector can be well electrically connected to the first pad and prevent the electrical connector from affecting the connection between the first voltage test point and the test probe. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0034] Figure 1 A schematic diagram of a back contact battery provided in an embodiment of the present application;

[0035] Figure 2 A schematic diagram of a back contact battery provided in another embodiment of the present application;

[0036] Figure 3 A schematic diagram of a back-contact battery provided in accordance with another embodiment of the present application.

[0037] Reference numerals:

[0038] 1-first voltage test point, 2-first end conductive member, 3-first pad, 4-second end conductive member, 5-second fine gate, 6-first fine gate, 7-second voltage test point, 8-second pad, 9-first interface layer, 10-first doped layer, 11-second doped layer, 12-second interface layer, 13-semiconductor substrate;

[0039] A-first area, B-second area. DETAILED DESCRIPTION

[0040] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0041] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0042] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "multiple" means two or more, unless otherwise clearly and specifically defined. "Several" means one or more, unless otherwise clearly and specifically defined.

[0043] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", etc., indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present application.

[0044] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0045] As described in the background technology, the back-contact solar cell has no grid lines on the front, completely avoiding the efficiency loss caused by grid line shading; however, since the P / N junction is on the back, it needs to set up twice as many main grids on the back for convergence compared to conventional cells, and to reduce the risk of short circuit, the opposite polarity thin grids next to the main grid need to be interrupted. Therefore, the existence of the main grid limits the space for cost reduction and efficiency improvement.

[0046] In order to balance efficiency and cost, some manufacturers have cancelled the main grid design of back-contact batteries, and only retain the welding pad points at the fixed positions of the fine grids. The P / N fine grids are designed to be completely through-type fingers, thereby achieving better cost and performance. However, in the past, when conducting IV and EL tests, the test probes were often electrically connected to the main grid for testing. The IV test is responsible for collecting battery performance data, mainly by irradiating the battery, using current needles and voltage needles to collect corresponding IV data and calculate performance; the EL test is responsible for inspecting battery defects, mainly by energizing the battery with current needles, stimulating the fluorescence effect, and collecting battery performance images. After the main grid design of the back-contact battery is cancelled, the test probe cannot stably contact the fine grid, making the test more difficult, and the reliability and stability are poor.

[0047] In view of the above situation, the present application provides a back-contact battery to facilitate the electrical connection between the test probe and the fine grid, thereby reducing the difficulty of testing.

[0048] See also Figure 1 The back-contact battery provided in the embodiment of the present application includes a battery body, a first fine grid 6, a second fine grid 5, a first end conductive member 2 and a first voltage test point 1. Among them, the battery body includes a first surface and a second surface that are arranged opposite to each other. Specifically, the first surface and the second surface are arranged opposite to each other along the thickness direction of the battery body. The first surface has a first side and a second side that are arranged opposite to each other along the first direction, that is, the first side and the second side are arranged in sequence along the first direction, and the first side and the second side can both be arranged perpendicular to the first direction. The first surface has a third side and a fourth side that are arranged opposite to each other along the second direction, that is, the third side and the fourth side are arranged in sequence along the second direction, and the third side and the fourth side can both be arranged perpendicular to the second direction. The two ends of the first side are respectively connected to the third side and the fourth side, and the two ends of the second side are respectively connected to the third side and the fourth side.

[0049] The first surface further includes a first region A close to the first edge, that is, the first region A is disposed adjacent to the first edge.

[0050] Specifically, the battery body includes a semiconductor substrate 13, a first doping layer 10 and a second doping layer 11. The first doping layer 10 and the second doping layer 11 have opposite conductivity types to collect and extract electrons and holes respectively, which is conducive to the formation of photocurrent. The first doping layer 10 and the second doping layer 11 are arranged on the first surface of the semiconductor substrate 13, and are alternately distributed along the first direction; specifically, the first doping layer 10 and the second doping layer 11 can be alternately distributed in strips, or can be alternately distributed in interdigitated shapes. There is an isolation region between the first doping layer 10 and the second doping layer 11 to reduce the carrier recombination rate at the lateral junction of the first doping layer 10 and the second doping layer 11, which is conducive to improving the photoelectric conversion efficiency of the back contact battery.

[0051] There are multiple first fine gates 6 and multiple second fine gates 5, and the multiple first fine gates 6 and multiple second fine gates 5 are all arranged on the first surface and are alternately distributed along the first direction; the multiple first fine gates 6 and multiple second fine gates 5 extend along the second direction, and the first fine gates 6 and the second fine gates 5 have different polarities. Specifically, the first fine gate 6 is arranged on the first doping layer 10 to use the first fine gate 6 to export the carriers collected by the first doping layer 10; the second fine gate 5 is arranged on the second doping layer 11 to use the second fine gate 5 to export the carriers collected by the second doping layer 11.

[0052] The first direction intersects with the second direction, that is, the first direction is different from the second direction, and the angle between the first direction and the second direction can be an acute angle or a right angle. For example, the first direction is set parallel to the third side and the fourth side, and the second direction is set parallel to the first side and the second side.

[0053] The first end conductive member 2 is arranged on the first area A and extends along the first direction, that is, the length direction of the first end conductive member 2 extends along the first direction. The first end conductive member 2 connects at least two first fine grids 6. Specifically, the plurality of first fine grids 6 adjacent to each other along the first direction are electrically connected to the first end conductive member 2, so that the currents of the plurality of adjacent first fine grids 6 are converged by the first end conductive member 2. Further, the plurality of adjacent first fine grids 6 close to the first side are electrically connected to the first end conductive member 2, that is, along the direction from the first side to the second side, the currents of the plurality of first fine grids 6 close to the first side and arranged adjacently are led out to the electrical connector (which may be a welding strip or a main grid) through the first end conductive member 2. In this way, the electrical connector is electrically connected to the first end conductive member 2, and the electrical connector does not need to extend to the vicinity of the first side, thereby avoiding the situation where the electrical connector extending to the vicinity of the first side is easily shaken and misaligned, resulting in leakage. In addition, the second fine grid 5 is interrupted at the first end conductive member 2 to prevent the first end conductive member 2 from contacting the second fine grid 5, thereby avoiding the risk of leakage.

[0054] In addition, at least one first end conductive member 2 has a first voltage test point 1. The first voltage test point 1 can be any component that cooperates with the test probe or an area that cooperates with the test probe. For example, the first voltage test point 1 can be an open voltage needle. In this way, during the IV or EL test process, the test probe used in the IV or EL test is electrically connected to the first voltage test point 1, and the first voltage test point 1 and the test probe can be in stable contact, so that a stable electrical connection is formed between the test probe and the first voltage test point 1, thereby reducing the test difficulty and improving the reliability and stability of the IV or EL test.

[0055] In some embodiments, Figure 1 As shown, the width of the first voltage test point 1 along the second direction is greater than the width of the first end conductive member 2 along the second direction. In other words, along the second direction, the two side edges of the first voltage test point 1 respectively exceed the two side edges of the first end conductive member 2. Such an arrangement widens the width of the first voltage test point 1 along the second direction, which is beneficial to provide a contact area between the first voltage test point 1 and the test probe, and further ensures that a stable electrical connection is formed between the test probe and the first voltage test point 1.

[0056] In other embodiments, Figure 1 As shown, the first voltage test point 1 is arranged at the intersection of the first thin grid 6 and the first end conductive member 2. With this technical solution, along the second direction, the first voltage test point 1 is aligned with a first thin grid 6, and the current of the first thin grid 6 can flow to the first voltage test point 1 along the shortest distance, shortening the flow distance of the current, thereby reducing the current loss, and further improving the reliability and stability of the test.

[0057] In some embodiments, Figure 1 As shown, the first end conductive member 2 includes a first end away from the first edge, that is, along the first direction, the two ends of the first end conductive member 2 are respectively a first end and a second end, the first end is closer to the second edge than the second end, and the second end is closer to the first edge than the first end. The distance between the first voltage test point 1 and the first end is S1, the length of the first end conductive member 2 along the first direction is L1, and S1 / L1 is less than or equal to 0.5. Such a setting can prevent the first voltage test point 1 from extending too long along the first direction, resulting in excessive transmission resistance of the first voltage test point 1, affecting the accuracy of the test. At the same time, during string welding, even if the end of the electrical connector (welding strip) extends above the first voltage test point 1 due to an error, it can protect the first fine grid 6 from being welded off, so the first voltage test point 1 needs to be slightly close to the first pad 3. Optionally, S1 / L1 is less than or equal to 0.4.

[0058] Illustratively, S1 / L1 may be 0.5, 0.45, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.1 or 0.05, etc.

[0059] like Figure 1 As shown, the back contact cell further includes a first pad 3 disposed in the first region A, the first pad 3 being electrically connected to the first end of the first end conductive member 2, and the first pad 3 being disposed close to the boundary between the first region A and the second region B. Specifically, the first pad 3 is located between the first end and the edge of the first region A, and the current flowing into the first end conductive member 2 from the plurality of first fine grids 6 eventually flows to the electrical connector through the first pad 3. Such a configuration makes it easier to electrically connect the first end conductive member 2 to the electrical connector.

[0060] Furthermore, the first pad 3 is connected to at least one first fine grid 6. With this arrangement, the current of the first fine grid 6 connected to the first pad 3 can flow directly to the first pad 3, ensuring that the current of the first fine grid 6 connected to the first pad 3 can flow to the first pad 3 along the shortest distance, shortening the flow distance of the current, thereby reducing the current loss, and further improving the reliability and stability of the test. Of course, the first fine grid 6 connected to the first pad 3 can be one, two, three or more.

[0061] In some embodiments, the first voltage test point 1 has the same width as the first pad 3 along the second direction. In other words, along the second direction, the first voltage test point 1 has the same extension distance as the first pad 3. With this technical solution, the first voltage test point 1 and the first pad 3 can be aligned to ensure that the first thin grid 6 aligned with the first voltage test point 1 and the first thin grid 6 connected to the first pad 3 are equal in length, and the current distribution is more uniform, thereby reducing current loss.

[0062] In some embodiments, Figure 3 As shown, in the first region A, the battery body includes a plurality of laminated parts, the plurality of laminated parts are arranged at intervals along the first direction, and the laminated part includes a first doping layer 10 and a second doping layer 11 arranged in a laminated manner. Specifically, along the first direction, the second doping layer 11 extends to a side of the first doping layer 10 that is away from the semiconductor substrate 13 to form a laminated part. The first voltage test point 1 is set on a laminated part. Since the height of the laminated part is relatively high, the first voltage test point 1 is set on the laminated part, which makes it easier to identify the first voltage test point 1 during the test process, which is conducive to improving the test efficiency.

[0063] Among them, the material of the semiconductor substrate 13 can be selected from materials such as silicon (Si) or germanium (Ge) or materials such as gallium arsenide (GaAs). Obviously, in terms of conductivity type, the semiconductor substrate 13 can be an intrinsic conductive substrate, an n-type conductive substrate or a p-type conductive substrate. Optionally, the semiconductor substrate 13 is a p-type conductive substrate or an n-type conductive substrate. Compared with the intrinsic conductive substrate, the p-type conductive substrate or the n-type conductive substrate has better conductivity, so that the final solar cell has a lower body resistivity, thereby improving the efficiency of the solar cell.

[0064] In addition, the materials of the first doping layer 10 and the second doping layer 11 can be silicon (Si), germanium (Ge), silicon carbide (SiCx) or gallium arsenide (GaAs), etc. The first doping layer 10 can be additionally formed on the semiconductor substrate 13 by deposition technology, and can also be formed in the semiconductor substrate 13 by diffusion, ion implantation, etc.

[0065] In terms of conductivity type, the first doping layer 10 may be an n-type doping layer, and the second doping layer 11 may be a p-type doping layer; or, the first doping layer 10 may be a p-type doping layer, and the second doping layer 11 may be an n-type doping layer.

[0066] In addition, the materials of the first doping layer 10 and the second doping layer 11 may be silicon (Si), germanium (Ge), silicon carbide (SiCx) or gallium arsenide (GaAs), etc. Taking the case where the materials of the first doping layer 10 and the second doping layer 11 are both silicon (Si) as an example, the first doping layer 10 may be one or more of doped polycrystalline silicon, doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon. The second doping layer 11 may also be one or more of doped polycrystalline silicon, doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon.

[0067] like Figure 3 As shown, in some embodiments, the above-mentioned back contact battery may also include a first interface layer 9, which is at least located between the first doping layer 10 and the semiconductor substrate 13. In this case, the passivation contact structure composed of the first interface layer 9 and the first doping layer 10 has an excellent interface passivation effect, and can achieve selective collection of carriers, reduce the carrier recombination rate in the area where the first doping layer 10 is formed on the first surface of the semiconductor substrate 13, and further improve the photoelectric conversion efficiency of the back contact battery. The material and thickness of the first interface layer 9 can be set according to the material of the first doping layer 10 and actual needs, and are not specifically limited here.

[0068] Among them, the material of the above-mentioned first interface layer 9 can be determined according to the material of the first doping layer 10. For example: when the first doping layer 10 includes a doped polysilicon layer, the first interface layer 9 is a tunneling oxide layer; in this way, the first doping layer 10 and the first interface layer 9 form a tunneling oxide layer passivation contact, and the tunneling oxide layer passivation technology can form a tunneling film between the first electrode and the semiconductor substrate 13, isolating the electrode from contacting the semiconductor substrate 13, reducing contact recombination losses, and electrons can tunnel through the film without affecting current transfer. At the same time, passivation can bend the surface energy band, reduce the surface recombination losses of the silicon wafer, and effectively improve the front passivation and metal contact problems. For another example: when the first doping layer 10 includes a doped amorphous silicon layer, the first interface layer 9 includes an intrinsic amorphous silicon layer. Secondly, the embodiment of the present invention does not specifically limit the material of the first interface layer 9.

[0069] In some embodiments, the back contact cell may further include a second interface layer 12, which is at least located between the second doped layer 11 and the semiconductor substrate 13. The projection of the second interface layer 12 on the semiconductor substrate 13 may overlap with the projection of the second doped layer 11 on the semiconductor substrate 13. In this case, the passivation contact structure composed of the second interface layer 12 and the second doped layer 11 can realize the selective collection of carriers and reduce the carrier recombination rate in the region where the second doped layer 11 is formed on the first surface of the semiconductor substrate 13. The material and thickness of the second interface layer 12 can be set according to the material of the second doped layer 11 and actual needs, and are not specifically limited here. For example: when the material of the second doped layer 11 includes one or more of doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon, the second interface layer 12 includes one or more of an intrinsic amorphous silicon layer, an intrinsic microcrystalline silicon layer, and an intrinsic nanocrystalline silicon. For another example, when the material of the second doped layer 11 includes doped polycrystalline silicon, the second interface layer 12 includes a tunneling oxide layer.

[0070] In other embodiments, Figure 1 As shown, the back contact battery also includes a second area B, the first area A and the second area B are arranged in sequence along the first direction, and there are two first areas A, one of which is closer to the first edge and the other is closer to the second edge, and the second area B is arranged between the two first areas A.

[0071] The back contact cell further includes a plurality of second pads 8 disposed in the second region B, the plurality of second pads 8 being electrically connected to the first fine grid 6 located in the second region B, and being arranged at intervals along the first direction. Specifically, the plurality of second pads 8 are arranged at intervals in sequence along the second direction, and each second pad 8 is conductively connected to the first fine grid 6 in the second region B, so that conductive connection between the first fine grid 6 and the electrical connection is achieved through the second pads 8, so that the current in the first fine grid 6 on the second region B can flow to the electrical connection along the shortest distance, thereby reducing current loss.

[0072] Further, along the second direction, the width of the first voltage test point 1, the width of the first pad 3, and the width of the second pad 8 are equal. Specifically, along the second direction, the first voltage test point 1, the first pad 3, and the second pad 8 can be aligned to ensure that the lengths of the first fine grid 6 connected to the first voltage test point 1, the first fine grid 6 connected to the first pad 3, and the first fine grid 6 connected to the second pad 8 are equal, and the current distribution is more uniform, thereby reducing current loss.

[0073] Along the first direction, the extension distance of the first voltage test point 1 and the extension distance of the second pad 8 are both smaller than the extension distance of the first pad 3. It can be understood that the current in the multiple first fine grids 6 connected to the first end conductive member 2 and the first fine grids 6 directly connected to the first pad 3 are all conducted to the electrical connector through the first pad 3, so the current flowing through the first pad 3 is greater than the current flowing through the second pad 8 and the first voltage test point 1. In this technical solution, by making the extension distance of the first pad 3 along the first direction greater than the extension distance of the second pad 8 and the first voltage test point 1 along the first direction, the conductive volume of the first pad 3 is increased, the transmission resistance of the first pad 3 is reduced, and the current loss is reduced, thereby improving the power generation efficiency of the back contact battery.

[0074] Optionally, along the first direction, the extension distance of the first pad 3 is greater than or equal to the distance between adjacent first fine grids 6. With this arrangement, the first pad 3 can be directly electrically connected to two or one adjacent first fine grids 6, while avoiding the situation where the first pad 3 eventually contacts the second fine grid 5 due to the excessive extension distance along the first direction, thereby reducing the risk of leakage.

[0075] like Figure 1 and Figure 2As shown, the back contact battery also includes a second end conductive member 4, which is arranged in the first area A and extends along the first direction. That is, the length direction of the second end conductive member 4 extends along the first direction. The second end conductive member 4 connects at least two second fine grids 5. Specifically, multiple second fine grids 5 adjacent to each other along the first direction are electrically connected to the second end conductive member 4, so that the currents of the adjacent multiple second fine grids 5 are converged by the second end conductive member 4. Further, multiple adjacent second fine grids 5 close to the first side are electrically connected to the second end conductive member 4, that is, along the direction from the first side to the second side, the currents of the multiple second fine grids 5 close to the first side and arranged adjacently are conducted to the electrical connector (which may be a welding strip or a main grid) through the second end conductive member 4. In this way, the electrical connector is electrically connected to the second end conductive member 4, and the electrical connector does not have to extend to the vicinity of the first side, which avoids the situation where the electrical connector extending to the vicinity of the first side is easily shaken and misaligned, resulting in leakage. In addition, the first fine grid 6 is interrupted at the second end conductive member 4, which prevents the second end conductive member 4 from contacting the first fine grid 6, thereby avoiding the risk of electrical leakage.

[0076] The second end conductive members 4 and the first end conductive members 2 are alternately arranged in sequence along the second direction, at least one second end conductive member 4 is provided with a second voltage test point 7, and the second voltage test points 7 and the first voltage test points 1 on the adjacent second end conductive members 4 and the first end conductive member 2 are staggered along the first direction. It can be understood that in the actual test process, the first voltage test point 1 and the second voltage test point 7 are respectively connected to the positive and negative poles of the test equipment, so the first voltage test point 1 and the second voltage test point 7 are generally arranged in pairs.

[0077] Specifically, in the adjacent second end conductive member 4 and the first end conductive member 2, the second voltage test point 7 on the second end conductive member 4 and the first voltage test point 1 on the first end conductive member 2 are staggered along the first direction. With this technical solution, along the first direction, the first voltage test point 1 can be aligned with the first fine grid 6, and the second voltage test point 7 can be aligned with the second fine grid 5, so that the current in the first fine grid 6 aligned with the first voltage test point 1 and the second fine grid 5 aligned with the second voltage test point 7 can flow to the voltage test point through the shortest distance, further reducing the current loss.

[0078] In some embodiments, Figure 2 As shown, a plurality of first end conductive members 2 and second end conductive members 4 in the first region A are equally spaced and distributed along the second direction. Specifically, the distances between any adjacent first end conductive members 2 and second end conductive members 4 are the same.

[0079] Or, in other embodiments, Figure 3As shown, the plurality of first end conductive members 2 and the second end conductive members 4 of the first region A are spaced apart along the second direction, and the plurality of first end conductive members 2 are equally spaced along the second direction, and the plurality of second end conductive members 4 are equally spaced along the second direction; along the second direction, the spacing between adjacent first end conductive members 2 and second end conductive members 4 is smaller than the spacing between adjacent first end conductive members 2 or adjacent second end conductive members 4. In this technical solution, the distance between any adjacent first end conductive members 2 is the same, the distance between any adjacent second end conductive members 4 is the same, and the distance between any adjacent first end conductive members 2 is smaller, and such a setting can make the edge current be collected more evenly by the electrical connector.

[0080] In some embodiments, the first area A is evenly divided into two parts along the second direction, and a voltage test point is provided on at least one first end conductive member 2 and at least one second end conductive member 4 in each part. With this technical solution, the first voltage test point 1 and the second voltage test point 7 are more evenly distributed in the first area A, thus avoiding the test error caused by uneven areas and further improving the accuracy of the back contact battery test.

[0081] like Figure 1 As shown, the back side of the back contact battery includes two first areas A and a second area B located between the two first areas A, that is, along the first direction, the second area B is located between the two first areas A. Any first area A is evenly divided into two parts, and at least one first end conductive member 2 and at least one second end conductive member 4 in each part have voltage test points. In this way, taking the center of the first surface as the origin, a coordinate axis is formed along the first direction and the second direction, and at least one pair of first voltage test points 1 and second voltage test points 7 are set in each of the four quadrants of the first surface, which further ensures the uniformity of the distribution of the voltage test points and reduces the test error caused by uneven areas.

[0082] For example, if the total number of the first end conductive members 2 and the second end conductive members 4 is 18, the voltage test points may be set only on some of the end conductive members, and of course, the voltage test points may also be set on all of the end conductive members. In the case of setting the voltage test points on some of the end conductive members, the voltage test points may be set on any two adjacent end conductive members from the 3rd to the 6th end conductive members along the first direction, and the voltage test points may be set on any two adjacent end conductive members from the 13th to the 16th end conductive members, so that at least one pair of the first voltage test point 1 and the second voltage test point 7 are set in each of the four quadrants of the first surface.

[0083] In some embodiments, Figure 1 and Figure 2As shown, in the first end conductive member 2 and the second end conductive member 4 adjacent to each other in the second direction, the first voltage test point 1 on the first end conductive member 2 is electrically connected to a first thin grid 6, and the second voltage test point 7 on the second end conductive member 4 is electrically connected to a second thin grid 5. With this technical solution, the current in the first thin grid 6 connected to the first voltage test point 1 and the second thin grid 5 connected to the second voltage test point 7 can flow to the first voltage test point 1 or the second voltage test point 7 at the shortest distance, further reducing the current loss and improving the accuracy of the test.

[0084] The above technical solution, such as Figure 1 As shown, in the first end conductive member 2 and the second end conductive member 4 adjacent to each other in the second direction, the first fine grid 6 electrically connected to the first voltage test point 1 on the first end conductive member 2 and the second fine grid 5 electrically connected to the second voltage test point 7 on the second end conductive member 4 are adjacently arranged in the first direction. In this way, the distance between the first voltage test point 1 and the second voltage test point 7 on the adjacent first end conductive member 2 and the second end conductive member 4 is smaller, and the accuracy of the test is higher.

[0085] Along the first direction, the difference between the extension distances of the first end conductive member 2 and the second end conductive member 4 is the spacing between the adjacent first fine grids 6 and second fine grids 5. This arrangement ensures that the first end conductive member 2 and the second end conductive member 4 are roughly aligned in the first direction, so that the currents flowing through the first end conductive member 2 and the second end conductive member 4 are roughly the same, avoiding the situation of excessive current and excessive temperature locally, and ensuring the stability of the performance of the entire back contact battery.

[0086] In other embodiments, Figure 1 As shown, at least one first fine grid 6 is spaced between the first fine grid 6 connected to the first voltage test point 1 on the first end conductive member 2 and the first pad 3. For example, one, two, three or more first fine grids 6 are spaced between the first fine grid 6 connected to the first voltage test point 1 on the first end conductive member 2 and the first pad 3. With this technical solution, the first voltage test point 1 is ensured to be far away from the first pad 3, so that the test is prevented from being affected by the convergence of the first pad 3, and the accuracy of the test is further improved.

[0087] In some embodiments, Figure 1As shown, the first end conductive member 2 is electrically connected to at least five first fine grids 6. That is, at least five first fine grids 6 closest to the first side are electrically connected to the first end conductive member 2. The second end conductive member 4 is electrically connected to at least five second fine grids 5. That is, at least five second fine grids 5 closest to the first side are electrically connected to the second end conductive member 4. In the case where the electrical connector is electrically connected to the first end conductive member 2 or the second end conductive member 4, the electrical connector does not need to extend to the vicinity of the first side, and the distance between the end of the electrical connector and the first side is large, which avoids the electrical connector extending to the vicinity of the first side from being easily shaken and misaligned, resulting in leakage.

[0088] Exemplarily, the first end conductive element 2 is electrically connected to five, six, seven or more first fine grids 6. The second end conductive element 4 is electrically connected to five, six, seven or more second fine grids 5.

[0089] In other embodiments, the width of the first end conductive member 2 along the second direction gradually decreases from the second region B to the first region A, that is, along the direction close to the first edge. Similarly, the width of the second end conductive member 4 along the second direction gradually decreases from the second region B to the first region A. It can be understood that the current flowing through the first end conductive member 2 or the second end conductive member 4 along the direction close to the second region B gradually increases, so in this technical solution, the width of the first end conductive member 2 or the second end conductive member 4 along the direction close to the second region B gradually increases, so that the transmission resistance of the first end conductive member 2 or the second end conductive member 4 gradually decreases, and the transmission resistance of the first end conductive member 2 or the second end conductive member 4 is adapted to the current inside it, further reducing the current loss, thereby improving the efficiency of the solar cell.

[0090] In addition, the embodiment of the present application further provides a photovoltaic module, which includes a back contact cell and an electrical connector provided in any of the above embodiments. The electrical connector is conductively connected to a plurality of first fine grids 6 or a plurality of second fine grids 5, wherein the electrical connector can be a main grid or a welding strip. Compared with the prior art, the beneficial effects of the photovoltaic module provided in the embodiment of the present application are the same as those of the above back contact cell, which will not be described in detail here.

[0091] In a specific embodiment, the back contact battery further includes a first pad 3 disposed in the first region A, the first pad 3 being electrically connected to the first end of the first end conductive member 2, and the first pad 3 being disposed close to the boundary between the first region A and the second region B. Along the first direction, the end of the electrical connector is located between the first pad 3 and the first voltage test point 1. Such an arrangement can ensure that the electrical connector can be well electrically connected to the first pad 3, and can also prevent the electrical connector from affecting the matching connection between the first voltage test point 1 and the test probe.

[0092] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0093] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A back contact battery, characterized in that: include: The battery body comprises a first surface and a second surface arranged opposite to each other, wherein the first surface comprises a first side and a second side arranged opposite to each other along a first direction, and a third side and a fourth side arranged opposite to each other along a second direction; and the first surface further comprises a first area close to the first side; A plurality of first fine grids and a plurality of second fine grids are arranged on the first surface, and are alternately distributed along a first direction and extend along a second direction, the first direction intersects the second direction, and the first fine grids and the second fine grids have different properties; A first end conductive member is disposed on the first region and extends along a first direction and connects at least two first fine grids, and the second fine grid is interrupted at the first end conductive member; At least one of the first end conductive members has a first voltage testing point.

2. The back contact cell according to claim 1, characterized in that: The width of the first voltage test point along the second direction is greater than the width of the first end conductive member along the second direction.

3. The back contact battery according to claim 1, characterized in that: The first voltage test point is disposed at an intersection of the first fine grid and the first end conductive member.

4. The back contact cell according to claim 1, characterized in that: The first end conductive member comprises a first end away from the first edge; The distance between the first voltage test point and the first end is S1, the length of the first end conductive piece along the first direction is L1, and S1 / L1 is less than or equal to 0.

5.

5. The back contact cell according to claim 1, characterized in that: The first end conductive member includes a first end away from the first side; the back contact battery also includes a first pad arranged in the first area, the first pad is electrically connected to the first end of the first end conductive member, and the first pad is connected to at least one first fine grid.

6. The back contact cell according to claim 5, characterized in that: The first voltage test point has the same width as the first pad along the second direction.

7. The back contact cell according to claim 1, characterized in that: In the first region, the battery body includes a plurality of stacked portions, the plurality of stacked portions are spaced apart along a first direction, and the stacked portions include a first doped layer and a second doped layer stacked together, and the first voltage test point is disposed on one of the stacked portions.

8. The back contact cell according to claim 1, characterized in that: It also includes a second region away from the first region and adjacent to the first region, wherein a plurality of second pads are disposed on the second region, the plurality of second pads are electrically connected to the first fine grid located in the second region, and are arranged at intervals along the first direction; Along the second direction, the width of the first voltage test point, the width of the first pad and the width of the second pad are equal; And / or, along the first direction, an extension distance of the first voltage test point and an extension distance of the second pad are both smaller than an extension distance of the first pad.

9. The back contact cell according to claim 1, characterized in that: It also includes a second end conductive member arranged in the first area and extending along the first direction, the second end conductive members and the first end conductive members are alternately arranged in sequence along the second direction, at least one of the second end conductive members is provided with a second voltage test point, and the second voltage test points and the first voltage test points on the adjacent second end conductive members and the first end conductive members are staggered along the first direction.

10. The back contact cell according to claim 9, characterized in that: The first area is equally divided into two parts along the second direction, and at least one of the first end conductive members and at least one of the second end conductive members in each part has a voltage test point; and / or, The back side of the back-contact battery includes two first areas and a second area located between the two first areas. Any first area is evenly divided into two parts, and at least one first end conductive member and at least one second end conductive member in each part have a voltage test point.

11. The back contact cell according to claim 9, characterized in that: In the first end conductive member and the second end conductive member adjacent to each other along the second direction, a first voltage test point on the first end conductive member is electrically connected to a first fine grid, and a second voltage test point on the second end conductive member is electrically connected to a second fine grid, and the first fine grid electrically connected to the first voltage test point and the second fine grid electrically connected to the second voltage test point are adjacently arranged along the first direction.

12. The back contact cell according to claim 1, characterized in that: The first end conductive member is electrically connected to at least five of the first fine grids.

13. The back contact cell according to claim 1, characterized in that: Along the direction approaching the first side, the width of the first end conductive member along the second direction gradually decreases.

14. A photovoltaic module, characterized in that: It comprises a back contact cell as claimed in any one of claims 1 to 13 and an electrical connector, wherein the electrical connector is electrically conductively connected to a plurality of the first fine grids.

15. The photovoltaic module according to claim 14, characterized in that: The first end conductive member includes a first end away from the first side; the back contact battery also includes a first pad disposed in the first region, the first pad being electrically connected to the first end of the first end conductive member; Along the first direction, an end of the electrical connector is located between the first pad and the first voltage test point.

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