Back contact battery and photovoltaic module

Abstract

The invention discloses a back contact cell and a photovoltaic module, relates to the technical field of photovoltaic, and aims to reduce parasitic absorption of a first doped region and a second doped region and facilitate improvement of the double-sided rate of the back contact cell. The back contact battery includes a battery body, and a first electrode and a second electrode disposed on the battery body. The first electrode is arranged on the first doped region and is electrically connected with the first doped region. The second electrode is arranged on the second doped region and is electrically connected with the second doped region. The first electrode and the second electrode each include a collector electrode. In the second direction, the part, located between two adjacent collector electrodes with opposite polarities, of the spacer region is a first spacer sub-region. And the width of the first doped sub-region is greater than or equal to that of the second doped sub-region. The width of the at least one first interval sub-region in the second direction is greater than the width of the at least one first doping sub-region in the second direction; and / or the area of the at least one first spacer sub-region is larger than the area of the at least one first doped sub-region.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic 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 back-facing 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] However, in existing back-contact cells, the first doped region and / or the second doped region arranged on the back side of the cell have high parasitic absorption, resulting in low light utilization on the back side, which is not conducive to improving the bifaciality of the back-contact cell. Summary of the invention

[0004] The object of the present invention is to provide a back contact cell and a photovoltaic module for reducing the parasitic absorption of the first doping region and the second doping region, improving the light utilization rate on one side of the first surface, and facilitating improving the bifaciality of the back contact cell.

[0005] In order to achieve the above-mentioned object, in a first aspect, the present invention provides a back contact battery, which includes: a battery body, and a first electrode and a second electrode arranged on the battery body. The battery body has a first surface and a second surface opposite to each other. The first surface includes a first doping region and a second doping region that are alternately spaced and distributed, and a spacer region between the first doping region and the second doping region. The first electrode is arranged on the first doping region and is electrically connected to the first doping region. The second electrode is arranged on the second doping region and is electrically connected to the second doping region. The first electrode and the second electrode both include a collector electrode. The collector electrode included in the first electrode and the collector electrode included in the second electrode extend along a first direction and are alternately spaced and distributed along a second direction. The first direction is different from the second direction. Along the second direction, the portion of the spacer region between two adjacent collector electrodes with opposite polarities is a first spacer sub-region. The portion of the first doping region located below the collector electrode included in the first electrode is a first doping sub-region, and the portion of the second doping region located below the collector electrode included in the second electrode is a second doping sub-region, and the width of the first doping sub-region is greater than or equal to the width of the second doping sub-region. The width of at least one first spacer sub-region along the second direction is greater than the width of at least one first doped sub-region along the second direction; and / or the area of ​​at least one first spacer sub-region is greater than the area of ​​at least one first doped sub-region.

[0006] In the case of adopting the above technical solution, when the back contact battery is in working state, the above first doping region and the second doping region can effectively shunt and collect carriers, which is conducive to the formation of photocurrent. The spacing region arranged between the first doping region and the second doping region is used to electrically isolate the first doping region and the second doping region of opposite conductivity type, thereby reducing the carrier recombination rate between the two. It can be understood that in the above spacing region, there is no doped semiconductor layer extending from the first doping region and / or the second doping region for shunting and collecting carriers and having parasitic absorption (or, the thickness of the doped semiconductor layer with parasitic absorption on the spacing region is less than the thickness of the doped semiconductor layer with parasitic absorption in the first doping region and / or the second doping region). Based on this, in the back contact battery provided by the present invention, the width of the first doped sub-region is greater than or equal to the width of the second doped sub-region. Furthermore, the width and / or area of ​​the first spacer sub-region located between two adjacent collector electrodes with opposite polarities is respectively greater than the width and / or area of ​​the first doped sub-region, which is conducive to increasing the area ratio of the spacer region in the first surface and reducing the leakage risk between the adjacent first doped sub-region and the second doped sub-region; at the same time, because the first doped region, the second doped region and the spacer region are located on the first surface, when the width and / or area of ​​the first spacer sub-region increases, the area ratio of the spacer region in the first surface increases, and the area ratio of the first doped sub-region and the second doped sub-region in the first surface decreases, which can reduce the parasitic absorption of the first doped sub-region and the second doped sub-region. Furthermore, when the area ratio of the first doped sub-region and the second doped sub-region in the first surface decreases, the light shielding area of ​​the collector electrodes respectively arranged on the first doped sub-region and the second doped sub-region will also decrease, thereby being able to improve the light utilization rate on one side of the first surface of the battery, which is conducive to improving the bifaciality of the back contact battery.

[0007] As a possible implementation scheme, the surface of the spacer has a suede structure, and the ratio of the total area of ​​all the spacers included in the first surface to the total area of ​​the first surface is greater than 50%.

[0008] When the above technical solution is adopted, when the ratio of the total area of ​​all the spacers included in the first surface to the total area of ​​the first surface is greater than 50%, the area of ​​the spacers accounts for a relatively large proportion, which can further reduce the parasitic absorption of the first doped region and the second doped region, and reduce the shading area of ​​the collector electrode. In addition, the velvet structure on the surface of the spacer has a light trapping effect, which can further improve the light utilization rate on the first side of the battery and further improve the double-sidedness of the back-contact battery. In addition, the surface of the spacer has an uneven velvet structure, which is conducive to increasing the specific surface area of ​​the spacer, increasing the passivation contact area between the spacer and the surface passivation layer, and is conducive to improving the open circuit voltage and short-circuit current of the battery.

[0009] As a possible implementation scheme, the ratio of the width of at least one first spacer sub-region to the sum of the widths of the adjacent first doped sub-region and the second doped sub-region is P1; 0.5<P1<3.

[0010] When the above technical solution is adopted, the ratio P1 is within the above range, which is conducive to preventing the width of the first doped sub-region and / or the second doped sub-region from being too large due to the ratio P1 being too small, further reducing the area ratio of the first doped region including the first doped sub-region and the second doped region including the second doped sub-region within the first surface, reducing the parasitic absorption of the two, and the shading area of ​​the collector electrode electrically connected to the two respectively; and when the surface of the spacer region has a velvet structure, the width of the first spacer sub-region is increased, and the area ratio of the surface of the first surface with the velvet structure can also be increased, further improving the light utilization rate on one side of the first surface of the battery. In addition, it can also prevent the width of the first doped sub-region and / or the second doped sub-region from being too small due to the ratio P1 being too large, which is beneficial for the first doped region and the second doped region to have a certain carrier diversion and collection ability, and is beneficial for the first side of the surface to have a relatively low carrier recombination rate; at the same time, it can also prevent the width of the collector electrode set on the first doped sub-region and / or the second doped sub-region from being too small due to the small width, thereby reducing the risk of the collector electrode breaking, and is beneficial to meeting the electrical interconnection requirements of the collector electrode and the auxiliary bus electrode or the interconnection structure, thereby reducing the interconnection resistance.

[0011] As a possible implementation scheme, along the second direction, the area between the midlines of two adjacent first doped sub-regions is the unit area, or the area between the midlines of two adjacent second doped sub-regions is the unit area. Along the second direction, the ratio between the width of a single first spacer sub-region and the width of the unit area is P2, and The application principle of the beneficial effect in this case is the same as the application principle of the beneficial effect of 0.5<P1<3 described above, and will not be repeated here. In addition, it can also prevent the carrier transmission distance of the first spacer region from being too large due to the width of the first spacer region being too large, reduce the probability of carrier loss such as radiation recombination during transmission, and help improve the conversion efficiency of the back contact battery.

[0012] As a possible implementation, in the back contact battery, along the second direction, the ratio of the total number of collector electrodes included in the first electrode and the collector electrodes included in the second electrode to the width of the first spacer region along the second direction is P3, and 0.1≤P3≤15.

[0013] When the above technical solution is adopted, the ratio P3 is within the above range, which is beneficial to prevent the width of the first spacer region from being too large due to the ratio P3 being too small, which is beneficial to shortening the lateral transmission distance of the carrier and reducing the lateral transmission loss. In addition, it is also possible to prevent the width of the first spacer region from being too small due to P3 being too large. The application principle of the beneficial effect of preventing the width of the first spacer region from being too small can be referred to in the previous text, and will not be repeated here. It should be noted that the ratio range of P3 is calculated by comparing the width of the first spacer region along the second direction in micrometers.

[0014] As a possible implementation, the first doped region is an emitter region. Moreover, the ratio between the cross-sectional area of ​​the first doped sub-region and the cross-sectional area of ​​the second doped sub-region is P4, 0.04<P4<30; or the ratio between the height-to-width ratio of the first doped sub-region and the height-to-width ratio of the second doped sub-region is P5, 0.04<P5<30.

[0015] In the case of adopting the above technical solution, when the first doped region is the emitter region, the first doped region can form a PN junction with the semiconductor substrate included in the battery body. It can be understood that the junction area and electric field strength of the built-in electric field of the PN junction will affect the shunting and collection rate of photogenerated carriers in the semiconductor substrate. Based on this, when P4 or P5 is greater than 0.04 and less than 30, the cross-sectional area or aspect ratio of the first doped sub-region included in the emitter region is respectively greater than the cross-sectional area or aspect ratio of the second doped sub-region included in the field region, which is beneficial to increase the junction area of ​​the above PN junction, and is beneficial to the improvement of the shunting and collection rate of carriers, and further reduces the carrier recombination rate. It should be noted that the ratio range of P5 is calculated by comparing the height unit in nanometers and the width unit in micrometers.

[0016] As a possible implementation scheme, a surface passivation layer is formed on one side of the first surface of the battery body. The collector electrode included in the first electrode penetrates the surface passivation layer and is electrically connected to the first doped region, and the collector electrode included in the second electrode penetrates the surface passivation layer and is electrically connected to the second doped region. The ratio between the width of the first spacer region along the second direction and the thickness of the surface passivation layer is P6, and 1000<P6<5000.

[0017] When the above technical solution is adopted, the size of the ratio P6 is within the above range, which is conducive to preventing the width of the first spacer region from being too small due to the ratio P6 being too small. The application principle of the beneficial effect of preventing the width of the first spacer region from being too small can be referred to the previous text, and will not be repeated here. In addition, it is also possible to prevent the width of the first spacer region from being too large and / or the thickness of the surface passivation layer from being too small due to the ratio P6 being too large, which is conducive to setting the width of the first spacer region and the thickness of the surface passivation layer within a reasonable range, so as to increase the width of the first spacer region relative to the prior art to reduce the parasitic absorption and the collector electrode shading area, while solving the problem of the passivation effect on one side of the first surface being poor due to the large width and / or area of ​​the spacer region, which is conducive to making one side of the first surface have a lower carrier recombination rate.

[0018] As a possible implementation scheme, the first electrode and the second electrode further include auxiliary bus electrodes. The auxiliary bus electrodes included in the first electrode and the auxiliary bus electrodes included in the second electrode both extend along the second direction and are alternately spaced and distributed along the first direction. The auxiliary bus electrodes included in the first electrode are electrically connected to at least part of the collector electrodes included in the first electrode, and the auxiliary bus electrodes included in the second electrode are electrically connected to at least part of the collector electrodes included in the second electrode. The collector electrode is disconnected at the intersection of the auxiliary bus electrodes with opposite polarity to itself. Along the first direction, the portion of the spacing region between the collector electrode and the auxiliary bus electrodes adjacent to itself and with opposite polarity is the second spacing sub-region. The portion of the first doped region located below the auxiliary bus electrode included in the first electrode is the third doped sub-region, and the portion of the second doped region located below the auxiliary bus electrode included in the second electrode is the fourth doped sub-region. Wherein, the width of the second spacing sub-region along the first direction is less than the width of the larger one of the third doped sub-region and the fourth doped sub-region; or, the area of ​​the second spacing sub-region is less than the area of ​​the larger one of the third doped sub-region and the fourth doped sub-region.

[0019] When the above technical solution is adopted, the width of the third doped sub-region and the fourth doped sub-region in the first direction is relatively large, which is beneficial for the first doped region and the second doped region to have higher carrier shunting and collection capabilities, and is beneficial for reducing the carrier recombination rate.

[0020] As a possible implementation scheme, the width of the third doped sub-region is greater than the width of the first doped sub-region. In this case, it is helpful to reduce the risk of leakage between the auxiliary bus electrode disposed above the third doped sub-region and the second doped region, and reduce the process difficulty of forming the auxiliary bus electrode above the third doped sub-region.

[0021] As a possible implementation scheme, the width of the fourth doped sub-region is greater than the width of the second doped sub-region. In this case, it is helpful to reduce the leakage risk between the auxiliary bus electrode arranged above the fourth doped sub-region and the first doped region, and reduce the process difficulty of forming the auxiliary bus electrode above the fourth doped sub-region.

[0022] As a possible implementation scheme, the first electrode and the second electrode also include an interconnection structure electrically connected to the collector electrode. The portion of the first doped region located below the interconnection structure included in the first electrode is the fifth doped sub-region, and the portion of the second doped region located below the interconnection structure included in the second electrode is the sixth doped sub-region. The width of the interconnection structure in the second direction is greater than the width of the collector electrode. The width of the fifth doped sub-region is greater than the width of the first doped sub-region. The width of the sixth doped sub-region is greater than the width of the second doped sub-region. This is conducive to reducing the risk of leakage between the interconnection structure and the heterogeneous doped region and improving the electrical reliability of the back contact battery.

[0023] As a possible implementation scheme, the first electrode and the second electrode also include an interconnection structure electrically connected to the collector electrode. The portion of the first doped region located below the interconnection structure included in the first electrode is the fifth doped sub-region, and the portion of the second doped region located below the interconnection structure included in the second electrode is the sixth doped sub-region. Wherein, the ratio between the width of the first spacer sub-region along the second direction and the width of the larger width of the fifth doped sub-region and the sixth doped sub-region along the second direction is greater than or equal to one-fiftieth and less than or equal to one-half; and / or, the ratio between the area of ​​the first spacer sub-region and the area of ​​the larger area of ​​the fifth doped sub-region and the sixth doped sub-region is greater than or equal to one-fiftieth and less than or equal to one-half. The application principle of the beneficial effect in this case is similar to the application principle of the beneficial effect of the width of the third doped sub-region being greater than the width of the first doped sub-region as described above, and will not be repeated here.

[0024] In a second aspect, the present invention provides a photovoltaic module, which includes a back-contact cell provided by the first aspect and various implementations thereof.

[0025] The beneficial effects of the second aspect of the present invention and its various implementations can be analyzed by referring to the beneficial effects of the first aspect and its various implementations, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0027] Figure 1 A schematic longitudinal cross-sectional view of a first structure of a back contact battery provided by an embodiment of the present invention;

[0028] Figure 2 Schematic diagram of the structure distribution on the back side of the back contact battery provided by the embodiment of the present invention Figure 1 ;

[0029] Figure 3 A schematic longitudinal cross-sectional view of a second structure of a back contact battery provided by an embodiment of the present invention;

[0030] Figure 4 A schematic longitudinal cross-sectional view of a third structure of a back contact battery provided by an embodiment of the present invention;

[0031] Figure 5 Schematic diagram of the structure distribution on the back side of the back contact battery provided by the embodiment of the present invention Figure 2 ;

[0032] Figure 6 Schematic diagram of the structure distribution on the back side of the back contact battery provided by the embodiment of the present invention Figure 3 ;

[0033] Figure 7 A schematic longitudinal cross-sectional view of a fourth structure of a back-contact battery provided by an embodiment of the present invention;

[0034] Figure 8 Schematic diagram of the structure distribution on the back side of the back contact battery provided by the embodiment of the present invention Figure 4 .

[0035] Figure numerals: 11 is the first doping region, 12 is the second doping region, 13 is the spacing region, 14 is the collector electrode, 15 is the first spacing sub-region, 16 is the first doping sub-region, 17 is the second doping sub-region, 18 is the unit region, 19 is the surface passivation layer, 20 is the auxiliary bus electrode, 21 is the second spacing sub-region, 22 is the third doping sub-region, 23 is the fourth doping sub-region, 24 is the interconnection structure, 25 is the fifth doping sub-region, 26 is the sixth doping sub-region, 27 is the semiconductor substrate, 28 is the first interface passivation layer, and 29 is the second interface passivation layer. DETAILED DESCRIPTION

[0036] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concept of the present invention.

[0037] Various structural schematic diagrams according to embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for a clearer expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0038] In the context of the present invention, when a layer / element is referred to as being "on" another layer / element, the layer / element may be directly on the other layer / element, or there may be an intermediate layer / element between them. In addition, if a layer / element is "on" another layer / element in one orientation, then when the orientation is reversed, the layer / element may be "under" the other layer / element. In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention 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 invention and are not used to limit the present invention.

[0039] 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 the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The meaning of "several" is one or more, unless otherwise clearly and specifically defined.

[0040] In the description of the present invention, 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 the present invention can be understood according to specific circumstances.

[0041] A solar cell is a device that can convert sunlight into electrical energy. Specifically, when the solar cell is in operation, sunlight shines on the semiconductor pn junction of the solar cell, forming new hole-electron pairs. Under the action of the built-in electric field of the pn junction, photogenerated holes flow to the p region, and photogenerated electrons flow to the n region. When the circuit is connected, current can be generated. Among them, a solar cell in which both the positive electrode and the negative electrode are on the back of the cell is a back-contact cell. Compared with a double-sided contact solar cell, the front of the back-contact cell is not blocked by a metal electrode, so that the light-facing side of the back-contact cell has a higher light utilization rate. Therefore, the back-contact cell has a higher short-circuit current and photoelectric conversion efficiency, and is one of the current technical directions for achieving high-efficiency crystalline silicon cells.

[0042] However, in the existing back-contact battery, in order to improve the efficiency of collecting carriers, the area of ​​the first doping region and the second doping region with opposite conductivity types arranged on the back of the battery accounts for a relatively high proportion (or the area of ​​one of the first doping region and the second doping region accounts for a relatively high proportion), and the manufacturing materials of the first doping region and the second doping region generally include light-absorbing semiconductor materials such as polycrystalline silicon, amorphous silicon, nanocrystalline silicon and microcrystalline silicon, resulting in high parasitic absorption in the first doping region and the second doping region. In addition, in order to timely guide the carriers collected by the first doping region and the second doping region with a relatively large area, the cross-sectional area and / or the number of the first electrode arranged on the first doping region and the second electrode arranged on the second doping region are also relatively large, and the corresponding first electrode and the second electrode have a relatively large light-shielding area, which leads to a low light utilization rate on the back side of the battery, which is not conducive to improving the bifaciality of the back-contact battery.

[0043] In order to solve the above technical problems, in the first aspect, an embodiment of the present invention provides a back contact battery. Figure 1 and Figure 2As shown, the back contact battery includes: a battery body, and a first electrode and a second electrode arranged on the battery body. The battery body has a first surface and a second surface opposite to each other. The first surface includes a first doping region 11 and a second doping region 12 that are alternately spaced, and a spacer region 13 located between the first doping region 11 and the second doping region 12. The first electrode is arranged on the first doping region 11 and is electrically connected to the first doping region 11. The second electrode is arranged on the second doping region 12 and is electrically connected to the second doping region 12. The first electrode and the second electrode both include a collector electrode 14. The collector electrode 14 included in the first electrode and the collector electrode 14 included in the second electrode extend along the first direction and are alternately spaced along the second direction. The first direction is different from the second direction. Along the second direction, the portion of the spacer region 13 located between two adjacent collector electrodes 14 with opposite polarities is a first spacer sub-region 15. The portion of the first doping region 11 located below the collector electrode 14 included in the first electrode is the first doping sub-region 16, the portion of the second doping region 12 located below the collector electrode 14 included in the second electrode is the second doping sub-region 17, and the width of the first doping sub-region 16 is greater than or equal to the width of the second doping sub-region 17. The width of at least one first spacer sub-region 15 along the second direction is greater than the width of at least one first doping sub-region 16 along the second direction; and / or the area of ​​at least one first spacer sub-region 15 is greater than the area of ​​at least one first doping sub-region 16.

[0044] It should be noted that “the portion of the first doped region located below the collector electrode included in the first electrode is the first doped sub-region” means that in the first doped region, the complete region below the collector electrode included in the first electrode is the first doped sub-region, and its portion not covered by the collector electrode included in the first electrode along the second direction also belongs to the first doped sub-region (that is, the portion of the region whose width is larger than the width of the collector electrode included in the first electrode also belongs to the first doped sub-region). In addition, “the portion of the second doped region located below the collector electrode included in the second electrode is the second doped sub-region” means that in the second doped region, the complete region below the collector electrode included in the second electrode is the second doped sub-region, and its portion not covered by the collector electrode included in the second electrode along the second direction also belongs to the second doped sub-region (that is, the portion of the region whose width is larger than the width of the collector electrode included in the second electrode also belongs to the second doped sub-region).

[0045] In the case of adopting the above technical solution, when the back contact battery is in working state, the above first doping region and the second doping region can effectively shunt and collect carriers, which is conducive to forming photocurrent. The spacing region arranged between the first doping region and the second doping region is used to electrically isolate the first doping region and the second doping region of opposite conductivity types, thereby reducing the carrier recombination rate between the two. It can be understood that if Figure 1 and Figure 2As shown, the spacer 13 does not have a doped semiconductor layer extending from the first doped region 11 and / or the second doped region 12 for shunting and collecting carriers and having parasitic absorption (or the thickness of the doped semiconductor layer with parasitic absorption on the spacer 13 is less than the thickness of the doped semiconductor layer with parasitic absorption in the first doped region 11 and / or the second doped region 12). Based on this, in the back contact battery provided by the embodiment of the present invention, the width of the first doped sub-region 16 is greater than or equal to the width of the second doped sub-region 17. Furthermore, the width and / or area of ​​the first spacer sub-region 15 located between two adjacent collector electrodes 14 with opposite polarities is respectively greater than the width and / or area of ​​the first doped sub-region 16, which is conducive to increasing the area ratio of the spacer region 13 in the first surface and reducing the leakage risk between the adjacent first doped sub-regions 16 and second doped sub-regions 17; at the same time, because the first doped region 11, the second doped region 12 and the spacer region 13 are all located on the first surface, when the width and / or area of ​​the first spacer sub-region 15 increases, the area ratio of the spacer region 13 in the first surface increases, and the area ratio of the first doped sub-region 16 and the second doped sub-region 17 in the first surface decreases, which can reduce the parasitic absorption of the first doped region 11 and the second doped region 12. Furthermore, when the area ratio of the first doped sub-region 16 and the second doped sub-region 17 in the first surface decreases, the light shielding area of ​​the collector electrode 14 respectively arranged on the first doped sub-region 16 and the second doped sub-region 17 will also decrease, thereby being able to improve the light utilization rate on one side of the first surface of the battery, which is conducive to improving the bifaciality of the back contact battery.

[0046] In actual application, the embodiments of the present invention do not impose any specific restrictions on the specific structure and materials of the battery body, as long as they can be applied to the back contact battery provided by the embodiments of the present invention.

[0047] Exemplarily, the battery body may include a semiconductor substrate, a first doping region, and a second doping region, wherein the first doping region is disposed on a local region of the semiconductor substrate corresponding to the first surface, and the second doping region is disposed on a local region of the semiconductor substrate corresponding to the second surface.

[0048] Among them, in the first doping region and the second doping region, only one of the materials may include a semiconductor material with parasitic absorption, or the materials of both may include a semiconductor material with parasitic absorption. Among them, the above-mentioned semiconductor material with parasitic absorption may be single crystal silicon, polycrystalline silicon, amorphous silicon, microcrystalline silicon and nanocrystalline silicon, etc. When the material of only one of the first doping region and the second doping region includes a semiconductor material with parasitic absorption, the semiconductor material without parasitic absorption included in the other may be determined according to the type of carriers transmitted by itself. For example: when the semiconductor material without parasitic absorption is used to collect electrons, the semiconductor material without parasitic absorption may be ZnO, SnO 2or TiO 2 Etc. Alternatively, when a semiconductor material without parasitic absorption is used to collect holes, the semiconductor material without parasitic absorption may be a copper aluminum sulfide compound or a copper aluminum oxide.

[0049] Of course, in the first doping region and the second doping region, the materials may include semiconductor materials with parasitic absorption as well as semiconductor materials without parasitic absorption.

[0050] Secondly, the materials of the first doping region and the second doping region may be the same or different. For example, the materials of the first doping region and the second doping region may both be polysilicon or amorphous silicon. For another example, the material of one of the first doping region and the second doping region is polysilicon, and the material of the other is amorphous silicon.

[0051] In addition, the embodiment of the present invention does not specifically limit the conductivity type of the first doping region and the second doping region. For example, the first doping region may be an N-type doping region, in which case the second doping region is a P-type doping region; or the first doping region may also be a P-type doping region, in which case the second doping region is an N-type doping region.

[0052] like Figure 1 As shown, the first doping region 11 can be directly disposed on the semiconductor substrate 27. Alternatively, as shown in FIG. Figure 3 As shown, the battery body may also include a first interface passivation layer 28 located between the semiconductor substrate 27 and the first doped region 11. The passivation contact structure composed of the first interface passivation layer 28 and the first doped region 11 has an excellent interface passivation effect, and can realize the selective collection of carriers, reduce the carrier recombination rate on the side of the semiconductor substrate 27 corresponding to the first surface, and further improve the photoelectric conversion efficiency of the back contact battery. The material and thickness of the first interface passivation layer 28 can be set according to the material of the first doped region 11 and actual needs, and are not specifically limited here. For example: when the first doped material is doped polycrystalline silicon, the first interface passivation layer is a tunneling passivation layer. For another example: when the material of the first doped region includes at least one of doped amorphous silicon, doped microcrystalline silicon and doped nanocrystalline silicon, the first interface passivation layer is an intrinsic amorphous silicon layer, an intrinsic microcrystalline silicon layer, an intrinsic nanocrystalline silicon layer or a mixed layer of the above three.

[0053] As for the second doped region, Figure 1 As shown, the second doping region 12 can be directly disposed on the semiconductor substrate 27. Alternatively, Figure 3As shown, the above-mentioned back contact cell may further include a second interface passivation layer 29 located between the semiconductor substrate 27 and the second doping region 12. In this case, the passivation contact structure composed of the second interface passivation layer 29 and the second doping region 12 can realize the selective collection of carriers and reduce the carrier recombination rate on the first side of the semiconductor substrate 27. The material and thickness of the second interface passivation layer 29 can refer to the setting principle of the material and thickness of the first interface passivation layer 28, which will not be repeated here.

[0054] In terms of surface morphology, Figure 3 As shown, in the first surface of the battery body, the surfaces of the first doping region 11 and the second doping region 12 can be planes. At this time, the surfaces of the semiconductor substrate 27 corresponding to the first doping region 11 and the second doping region 12 are also relatively flat, which is conducive to improving the formation quality of the first doping region 11 and the second doping region 12 on the semiconductor substrate 27, and improving the field passivation effect of the first doping region 11 and the second doping region 12. Alternatively, the surfaces of the first doping region and the second doping region can also be velvet to further improve the double-sidedness of the back contact battery; at the same time, it is conducive to increasing the contact area between the first doping region and the second doping region and the first electrode and the second electrode respectively, which is conducive to reducing the contact resistance. In this case, the embodiment of the present invention does not specifically limit the type and size of the velvet structure on the surface of the first doping region and the second doping region, and can be set according to actual needs.

[0055] As for the spacer in the first surface, the surface of the spacer may be a plane. Figure 4 As shown, the surface of the spacer 13 may also have a velvet structure. In this case, the velvet structure has a light-trapping effect, which can further improve the light utilization rate on one side of the first surface of the battery, and further improve the double-sidedness of the back-contact battery. In addition, the surface of the spacer 13 has an uneven velvet structure, which is beneficial to increase the specific surface area of ​​the spacer 13, increase the passivation contact area between the spacer 13 and the surface passivation layer 19, and help improve the open circuit voltage and short-circuit current of the battery. In this case, the embodiment of the present invention does not specifically limit the type and size of the velvet structure on the surface of the spacer 13, and can be set according to actual needs.

[0056] Exemplarily, the velvet structure on the surface of the spacer may be a pyramid structure. The one-dimensional dimension of the pyramid structure (the one-dimensional dimension may refer to the length of the bottom side or the diagonal length of the pyramid structure, or the height or the side edge length of the pyramid structure) may be greater than or equal to 0.5 μm and less than or equal to 5 μm. The top angle of the pyramid structure may be greater than or equal to 30° and less than or equal to 60°.

[0057] As for the shapes of the first doped region, the second doped region and the spacer region in the first surface, they can be set according to actual needs and are not specifically limited here.

[0058] For example, Figure 2 and 5 As shown, at least part of the first doping region 11 and at least part of the second doping region 12 may be distributed alternately and spaced in strips. In this case, both the first doping region 11 and the second doping region 12 include strip-shaped doping regions. Moreover, the strip-shaped doping regions included in the first doping region 11 and the second doping region 12 extend along the first direction and are distributed alternately and spaced along the second direction.

[0059] For example, Figure 5 and Figure 6 As shown, at least part of the first doping region 11 and at least part of the second doping region 12 can be distributed alternately at intervals in a forked finger shape. At this time, the first doping region 11 and the second doping region 12 both include strip-shaped doping regions and connecting doping regions. The strip-shaped doping regions included in the first doping region 11 and the second doping region 12 both extend along the first direction and are distributed alternately at intervals along the second direction. The connecting doping regions included in the first doping region 11 and the second doping region 12 both extend along the second direction and are distributed alternately at intervals along the first direction. The connecting doping regions included in the first doping region 11 are connected to at least part of the strip-shaped doping regions included in the first doping region 11, and the connecting doping regions included in the second doping region 12 are connected to at least part of the strip-shaped doping regions included in the second doping region 12.

[0060] The first direction and the second direction may be any two directions that are parallel to the first surface and different from each other. Optionally, the first direction and the second direction are orthogonal.

[0061] As for the area ratios of the first doped region, the second doped region and the spacer region in the first surface, and the differences between the widths of the first spacer sub-region and the first doped sub-region and the second doped sub-region, respectively, they can be determined according to the shapes of the first doped region and the second doped region in the actual application scenario, the parasitic absorption and carrier collection efficiency of the first doped region and the second doped region, and the requirements for the double-sidedness of the battery, as long as the width of at least one first spacer sub-region along the second direction is greater than the width of at least one first doped sub-region along the second direction; and / or the area of ​​at least one first spacer sub-region is greater than the area of ​​at least one first doped sub-region.

[0062] Exemplarily, the ratio of the total area of ​​all the spacers included in the first surface to the total area of ​​the first surface may be greater than 50%. For example, the ratio of the total area of ​​all the spacers included in the first surface to the total area of ​​the first surface may be 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59% or 60%, etc. In this case, the area of ​​the spacers accounts for a large proportion, which can further reduce the parasitic absorption of the first doping region and the second doping region, and reduce the light shielding area of ​​the collector electrode.

[0063] Exemplarily, the ratio of the width of at least one first spacer sub-region to the sum of the widths of the adjacent first doped sub-region and the second doped sub-region is P1; 0.5<P1<3. For example, the ratio P1 can be 0.51, 0.55, 0.6, 0.7, 0.8, 1, 1.2, 1.5, 1.8, 2, 2.2, 2.4, 2.6 or 2.8. In this case, the ratio P1 is within the above range, which is conducive to preventing the width of the first doped sub-region and / or the second doped sub-region from being too large due to the ratio P1 being too small, further reducing the area ratio of the first doped region including the first doped sub-region and the second doped region including the second doped sub-region in the first surface, reducing the parasitic absorption of the two, and the light shielding area of ​​the collector electrode electrically connected to the two; and in the case where the surface of the spacer region has a velvet structure, the width of the first spacer sub-region is increased, and the area ratio of the surface of the first surface provided with the velvet structure can also be increased, further improving the light utilization rate on one side of the first surface of the battery. In addition, it can also prevent the width of the first doped sub-region and / or the second doped sub-region from being too small due to the ratio P1 being too large, which is beneficial for the first doped region and the second doped region to have a certain carrier diversion and collection ability, and is beneficial for the first side of the surface to have a relatively low carrier recombination rate; at the same time, it can also prevent the width of the collector electrode set on the first doped sub-region and / or the second doped sub-region from being too small due to the small width, thereby reducing the risk of the collector electrode breaking, and is beneficial to meeting the electrical interconnection requirements of the collector electrode and the auxiliary bus electrode or the interconnection structure, thereby reducing the interconnection resistance.

[0064] For example, Figure 2 , Figure 5 and Figure 6 As shown, along the second direction, the area between the midlines of two adjacent first doped sub-regions 16 is the unit region 18, or the area between the midlines of two adjacent second doped sub-regions 17 is the unit region 18. Along the second direction, the ratio between the width of a single first spacer sub-region 15 and the width of the unit region 18 is P2, and For example, the ratio P2 can be 0.26, 0.28, 0.3, 0.4, 0.5, 0.6 or 0.65, etc. The application principle of the beneficial effect in this case is the same as the application principle of the beneficial effect of 0.5<P1<3 described above, and will not be repeated here. In addition, it can also prevent the carrier transmission distance of the first spacer region from being too large due to the width of the first spacer region being too large, reduce the probability of carrier losses such as radiation recombination during transmission, and help improve the conversion efficiency of the back contact battery.

[0065] In actual application, the cross-sectional area and / or aspect ratio of the first doping region and the second doping region may be the same.

[0066] Or, if Figure 2 , Figure 5and Figure 6 As shown, when the first doping region 11 is an emitter region, the ratio between the cross-sectional area of ​​the first doping sub-region 16 and the cross-sectional area of ​​the second doping sub-region 17 is P4, 0.04<P4<30; or, the ratio between the height-to-width ratio of the first doping sub-region 16 and the height-to-width ratio of the second doping sub-region 17 is P5, 0.04<P5<30. In this case, when the first doping region 11 is an emitter region, the first doping region 11 can form a PN junction with the semiconductor substrate 27 included in the battery body. It can be understood that the junction area and electric field strength of the built-in electric field of the PN junction will affect the shunting and collection rate of photogenerated carriers in the semiconductor substrate 27. Based on this, when P4 or P5 is greater than 0.04 and less than 30, the cross-sectional area or aspect ratio of the first doped sub-region 16 included in the emitter region is respectively greater than the cross-sectional area or aspect ratio of the second doped sub-region 17 included in the field region, which is beneficial to increase the junction area of ​​the above-mentioned PN junction, and is beneficial to improve the shunting and collection rate of carriers, and further reduce the carrier recombination rate. It should be noted that when the first doped region and the second doped region are doped semiconductor layers (such as doped amorphous silicon layers, doped polycrystalline silicon layers, doped single crystal silicon layers or doped microcrystalline silicon layers, etc.) arranged on the first surface of the semiconductor substrate, the aspect ratio of the first doped sub-region and / or the second doped sub-region refers to the ratio between the thickness and the width of the doped semiconductor layer.

[0067] Exemplarily, in the back contact battery, along the second direction, the ratio between the total number of collector electrodes included in the first electrode and the total number of collector electrodes included in the second electrode and the width of the first spacer region along the second direction is P3, and 0.1≤P3≤15. For example, the ratio P3 can be 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.5, 1, 3, 5, 8, 10, 12 or 15, etc. In this case, the ratio P3 is within the above range, which is beneficial to prevent the width of the first spacer region from being too large due to the ratio P3 being too small, and is beneficial to shortening the lateral transmission distance of the carriers and reducing the lateral transmission loss. In addition, it is also possible to prevent the width of the first spacer region from being too small due to P3 being too large. The application principle of the beneficial effect of preventing the width of the first spacer region from being too small can be referred to the previous text and will not be repeated here.

[0068] As for the dimensional information such as the width of the first doped sub-region, the second doped sub-region and the first spacing sub-region along the second direction and the length along the first direction, as well as the width and total number of the collecting electrodes included in the first electrode and the collecting electrodes included in the second electrode along the second direction, they can be set according to the size of the battery body in the actual application scenario and actual needs, and are not specifically limited here.

[0069] Exemplarily, the width of the first doped sub-region and / or the second doped sub-region in the second direction may be greater than or equal to 50 μm and less than or equal to 500 μm. For example, the width of the first doped sub-region and / or the second doped sub-region in the second direction may be 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm or 500 μm, etc. Optionally, the width of the first doped sub-region and / or the second doped sub-region in the second direction may be greater than or equal to 100 μm and less than or equal to 300 μm.

[0070] Exemplarily, the width of the first spacer sub-region in the second direction may be greater than or equal to 80 μm and less than or equal to 1000 μm. For example, the width of the first spacer sub-region in the second direction may be 80 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm or 1000 μm, etc. Optionally, the width of the first spacer sub-region in the second direction may be greater than or equal to 100 μm and less than or equal to 600 μm.

[0071] Exemplarily, the length of at least one of the first doped sub-region, the second doped sub-region, and the first spacer sub-region in the first direction may be greater than or equal to 0.05 mm and less than or equal to 300 mm. For example, the length of at least one of the first doped sub-region, the second doped sub-region, and the first spacer sub-region in the first direction may be 0.05 mm, 1 mm, 10 mm, 20 mm, 50 mm, 100 mm, 200 mm, or 300 mm, etc. Optionally, the width of at least one of the first doped sub-region, the second doped sub-region, and the first spacer sub-region in the second direction may be greater than or equal to 50 mm and less than or equal to 220 mm.

[0072] For example, the total area of ​​the first doped sub-region and / or the second doped sub-region within the first plane may be greater than or equal to 10 cm 2 , and less than or equal to 250cm 2 For example, the total area of ​​the first doped sub-region and / or the second doped sub-region within the first plane may be 10 cm 2 , 20cm 2 , 50cm 2 、80cm 2 、100cm 2 、120cm 2 、150cm 2 、180cm 2 , 200cm 2 or 250cm 2 Optionally, the total area of ​​the first doped sub-region and / or the second doped sub-region within the first plane may be greater than or equal to 40 cm 2, and less than or equal to 150cm 2 .

[0073] Exemplarily, the total area of ​​the spacer in the first surface may be greater than or equal to 20 cm 2 , and less than or equal to 300cm 2 For example, the total area of ​​the spacer in the first surface can be 20 cm 2 , 50cm 2 、80cm 2 、100cm 2 、120cm 2 、150cm 2 、180cm 2 , 200cm 2 、250cm 2 or 300cm 2 Optionally, the total area of ​​the spacing zone in the first surface may be greater than or equal to 80 cm 2 , and less than or equal to 250cm 2 .

[0074] As a possible implementation, Figure 7 As shown, a surface passivation layer 19 may be formed on one side of the first surface of the battery body to passivate the surface defects on one side of the first surface of the battery body and reduce the carrier recombination rate. In this case, the collector electrode 14 included in the first electrode passes through the surface passivation layer 19 and is electrically connected to the first doped region 11, and the collector electrode 14 included in the second electrode passes through the surface passivation layer 19 and is electrically connected to the second doped region 12. In addition, it can be understood that when the area proportion of the first doped region 11 and the second doped region 12 with field passivation on one side of the first surface is reduced, the presence of the surface passivation layer 19 can reduce the number of surface defects in the spacer region 13, which is beneficial to the first side of the battery body having a higher passivation effect. Therefore, the size relationship between the width of the first spacer region 15 and the thickness of the surface passivation layer 19 can be set according to actual needs, as long as it can be applied to the back contact battery provided in the embodiment of the present invention.

[0075] Exemplarily, the ratio between the width of the first spacer region along the second direction and the thickness of the surface passivation layer is P6, and 1000<P6<5000. For example, the ratio P6 can be 1001, 1100, 1200, 1500, 2000, 2500, 3000, 3500, 4000, 4500 or 4999, etc. In this case, the size of the ratio P6 is within the above range, which is conducive to preventing the width of the first spacer region from being too small due to the ratio P6 being too small. The application principle of the beneficial effect of preventing the width of the first spacer region from being too small can be referred to the previous text, and will not be repeated here. In addition, it can also prevent the width of the first spacer region from being too large and / or the thickness of the surface passivation layer from being too small due to the ratio P6 being too large, which is beneficial to setting the width of the first spacer region and the thickness of the surface passivation layer within a reasonable range, so as to increase the width of the first spacer region relative to the prior art to achieve the reduction of parasitic absorption and collector electrode shading area, while solving the problem of the passivation effect on one side of the first surface being deteriorated due to the small area of ​​the first doped region and the second doped region with field passivation effect, which is beneficial to making one side of the first surface have a lower carrier recombination rate.

[0076] In addition, the material of the surface passivation layer may include any insulating material with a passivation effect, which is not specifically limited here. For example, the material of the surface passivation layer may include at least one of silicon oxide, silicon nitride and aluminum oxide.

[0077] For the first electrode and the second electrode, specific structures of the first electrode and the second electrode can be determined according to the shapes of the first doping region and the second doping region, respectively, and are not specifically limited here.

[0078] For example, Figure 2 As shown, when the first doping regions 11 and the second doping regions 12 are alternately spaced and distributed in an interdigitated manner, the first electrode and the second electrode may only include the collector electrode 14 .

[0079] For example, Figure 5 and Figure 6 As shown, the first electrode and the second electrode may further include an auxiliary bus electrode 20. The auxiliary bus electrode 20 included in the first electrode and the auxiliary bus electrode 20 included in the second electrode both extend along the second direction and are alternately spaced along the first direction. The auxiliary bus electrode 20 included in the first electrode is electrically connected to at least part of the collector electrode 14 included in the first electrode, and the auxiliary bus electrode 20 included in the second electrode is electrically connected to at least part of the collector electrode 14 included in the second electrode. The collector electrode 14 is disconnected at the intersection with the auxiliary bus electrode 20 of the opposite polarity to itself.

[0080] Among them, Figure 5As shown, in the first electrode, the same auxiliary bus electrode 20 can be electrically connected to only some rows of collector electrodes 14 spaced apart along the second direction; and in the second electrode, the auxiliary bus electrode 20 can be electrically connected to only some rows of collector electrodes 14 spaced apart along the second direction. Figure 6 As shown, in the first electrode, the auxiliary bus electrode 20 can also be electrically connected to all rows of collector electrodes 14 spaced apart along the second direction; and in the second electrode, the auxiliary bus electrode 20 can also be electrically connected to all rows of collector electrodes 14 spaced apart along the second direction.

[0081] The length of the auxiliary bus electrode along the second direction and the width along the first direction can be set according to actual needs and are not specifically limited here. In some examples, the width of the auxiliary bus electrode along the first direction can be greater than the width of the collector electrode along the second direction to increase the carrier conduction area of ​​the auxiliary bus electrode and reduce transmission loss.

[0082] Exemplarily, the width of at least one auxiliary bus electrode along the first direction may be greater than or equal to 0.05 mm and less than or equal to 300 mm. For example, the width of at least one auxiliary bus electrode along the first direction may be 0.05 mm, 0.1 mm, 1 mm, 10 mm, 50 mm, 80 mm, 100 mm, 150 mm, 200 mm, 250 mm or 300 mm, etc. Optionally, the width of at least one auxiliary bus electrode along the first direction may be greater than or equal to 0.5 mm and less than or equal to 100 mm.

[0083] Among them, the widths of the auxiliary bus electrode in different regions along the second direction may be the same or different. For example, the width of the auxiliary bus electrode from the midline to both ends along the second direction may gradually decrease. In addition, when the width of the auxiliary bus electrode changes, the width of the first doping region and / or the second doping region located below the corresponding auxiliary bus electrode may also change in the same trend as the width of the auxiliary bus electrode, that is, when the width of the auxiliary bus electrode becomes smaller, the width of the first doping region and / or the second doping region located below the smaller width of the corresponding auxiliary bus electrode is also smaller.

[0084] As for the spacing along the first direction between the auxiliary bus electrode and the collector electrode of opposite conductivity type to itself, it can be determined according to the requirements for leakage prevention between the two in actual application scenarios and the requirements for the carrier collection ability of the collector electrode, and is not specifically limited here.

[0085] The spacing between the auxiliary bus electrodes of the first electrode and the corresponding collector electrodes of the second electrode along the first direction may be the same as or different from the spacing between the auxiliary bus electrodes of the second electrode and the corresponding collector electrodes of the first electrode along the first direction.

[0086] For example, when the first electrode is a positive electrode and the second electrode is a negative electrode, the spacing between the auxiliary bus electrode included in the first electrode and the corresponding collector electrode included in the second electrode along the first direction may be greater than the spacing between the auxiliary bus electrode included in the second electrode and the corresponding collector electrode included in the first electrode along the first direction. At this time, the spacing between the auxiliary bus electrode included in the second electrode and the corresponding collector electrode included in the first electrode along the first direction is small, which is conducive to increasing the length of the collector electrode included in the first electrode and improving the carrier collection capacity of the collector electrode included in the first electrode.

[0087] In addition, when the first electrode and the second electrode also include an auxiliary bus electrode, if the auxiliary bus electrode is a burn-through type electrode, then at least the area corresponding to the auxiliary bus electrode in the first doping region and the second doping region is distributed alternately and spaced in a forked finger shape; along the first direction, the strip-shaped doping regions in the same row and with the same conductivity type are disconnected at the intersection with the connecting doping region of the opposite conductivity type.

[0088] If the auxiliary bus electrode is a non-burn-through electrode, the first doping region and the second doping region can be distributed alternately in strips, that is, the area of ​​the auxiliary bus electrode that does not intersect with the collector electrode of the same conductivity type along the length direction is not arranged above the doping region of the same conductivity type as itself. In this case, the auxiliary bus electrode can be electrically isolated from the doping region of the opposite conductivity type to itself and located below itself by a film layer made of insulating materials such as a surface passivation layer. Or, Figure 5 and Figure 6 As shown, when the auxiliary bus electrode 20 is a non-burn-through type electrode, at least the area corresponding to the auxiliary bus electrode 20 in the first doping area 11 and the second doping area 12 can also be distributed alternately and spaced in a forked finger shape; along the first direction, the strip-shaped doping areas in the same row and with the same conductivity type are disconnected at the intersection with the connecting doping area of ​​the opposite conductivity type to prevent short circuit.

[0089] Among them, in the region where the first doping region and the second doping region are alternately distributed in an interdigitated manner, the portion of the spacing region located between the collector electrode and the auxiliary bus electrode adjacent to the collector electrode and having the opposite polarity is defined as the second spacing sub-region along the first direction. The portion of the first doping region located below the auxiliary bus electrode included in the first electrode is the third doping sub-region, and the portion of the second doping region located below the auxiliary bus electrode included in the second electrode is the fourth doping sub-region.

[0090] The width of the above-mentioned second spacer region along the first direction can be equal to the width of the third doped sub-region and / or the fourth doped sub-region along the first direction. At this time, the width of the second spacer region is larger, and the distance between the corresponding auxiliary bus electrode and the end of the collector electrode with opposite polarity to itself and intersecting extension line is larger, thereby reducing the risk of leakage between the two.

[0091] Or, if Figure 5 and Figure 6 As shown, the width of the second spacer sub-region 21 along the first direction may also be smaller than the width of the larger one of the third doped sub-region 22 and the fourth doped sub-region 23; or, the area of ​​the second spacer sub-region 21 may be smaller than the area of ​​the larger one of the third doped sub-region 22 and the fourth doped sub-region 23. In this case, the third doped sub-region 22 and the fourth doped sub-region 23 have a larger width in the first direction, which is conducive to making the first doped region 11 and the second doped region 12 have a higher carrier shunting and collection ability, and is conducive to reducing the carrier recombination rate. At the same time, it is conducive to retaining sufficient carrier collection space and improving the current collection ability.

[0092] In addition, the width of the third doped sub-region may be equal to the width of the first doped sub-region; or Figure 5 and Figure 6 As shown, the width of the third doped sub-region 22 may be greater than the width of the first doped sub-region 16. In this case, it is helpful to reduce the risk of leakage between the auxiliary bus electrode 20 disposed above the third doped sub-region 22 and the second doped region 12, and reduce the process difficulty of forming the auxiliary bus electrode 20 above the third doped sub-region 22.

[0093] The width of the fourth doped sub-region may be equal to the width of the second doped sub-region; or Figure 5 and Figure 6 As shown, the width of the fourth doped sub-region 23 is greater than the width of the second doped sub-region 17. In this case, it is helpful to reduce the risk of leakage between the auxiliary bus electrode 20 disposed above the fourth doped sub-region 23 and the first doped region 11, and reduce the process difficulty of forming the auxiliary bus electrode 20 above the fourth doped sub-region 23.

[0094] As for the size information such as the width of the third doped sub-region, the fourth doped sub-region and the second spacer sub-region along the first direction, it can be set according to the size of the battery body in the actual application scenario and actual needs, and is not specifically limited here.

[0095] As a possible implementation, Figure 8 As shown, the first electrode and the second electrode may further include an interconnection structure 24 electrically connected to the collector electrode 14, for realizing electrical interconnection between different batteries. The shape of the interconnection structure 24, the distribution and number of the interconnection structure 24 on the battery body, and the size of the interconnection structure 24 can be set according to actual needs, and are not specifically limited here.

[0096] The width of the interconnection structure in the second direction may be equal to the width of the collector electrode, or may be greater than the width of the collector electrode.

[0097] Exemplarily, the length of at least one interconnection structure along the first direction may be greater than or equal to 0.05 mm and less than or equal to 300 mm. For example, the length of at least one interconnection structure along the first direction may be 0.05 mm, 0.1 mm, 1 mm, 10 mm, 50 mm, 80 mm, 100 mm, 150 mm, 200 mm, 250 mm or 300 mm, etc. Optionally, the length of at least one interconnection structure along the first direction may be greater than or equal to 0.5 mm and less than or equal to 100 mm.

[0098] Exemplarily, the width of at least one interconnect structure along the second direction may be greater than or equal to 50 μm and less than or equal to 800 μm. For example, the width of at least one interconnect structure along the second direction may be 50 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm or 800 μm, etc. Optionally, the width of at least one interconnect structure along the second direction may be greater than or equal to 200 μm and less than or equal to 500 μm.

[0099] For example, the area of ​​all interconnected structures included in the first electrode and / or the second electrode on one side of the first surface may be greater than or equal to 0.1 cm 2 , and less than or equal to 100cm 2 For example, the area of ​​all interconnected structures included in the first electrode and / or the second electrode on one side of the first surface may account for 0.1 cm 2 , 1cm 2 , 5cm 2 、10cm 2 , 20cm 2 , 50cm 2 、60cm 2 、80cm 2 or 100cm 2 Optionally, the area of ​​all interconnected structures included in the first electrode and / or the second electrode on one side of the first surface may be greater than or equal to 1 cm 2 , and less than or equal to 50cm 2 .

[0100] For example, in a single unit region, the number of interconnect structures disposed above the first doping region and / or the second doping region may be greater than or equal to 2 and less than or equal to 50.

[0101] For example, on the first surface, the total number of interconnect structures disposed above the first doping region and / or the second doping region may be greater than or equal to 100 and less than or equal to 3,000.

[0102] In addition, if Figure 8As shown, the portion of the first doped region 11 located below the interconnection structure 24 included in the first electrode is defined as the fifth doped sub-region 25, and the portion of the second doped region 12 located below the interconnection structure 24 included in the second electrode is defined as the sixth doped sub-region 26. In this case, when the width of the interconnection structure 24 along the second direction is greater than the width of the collector electrode 14, the width of the fifth doped sub-region 25 is greater than the width of the first doped sub-region 16. The width of the sixth doped sub-region 26 is greater than the width of the second doped sub-region 17, so as to reduce the risk of leakage between the interconnection structure 24 and the heterogeneous doped region and improve the electrical reliability of the back contact battery.

[0103] As for the width of the fifth doped sub-region and the sixth doped sub-region, they can be determined according to the size of the interconnection structure and the requirements for the double-sidedness of the back contact battery in the actual application scenario, and are not specifically limited here.

[0104] Exemplarily, the ratio of the width of the first spacer sub-region along the second direction to the width of the larger width of the fifth doped sub-region and the sixth doped sub-region along the second direction may be greater than or equal to one-fiftieth and less than or equal to one-half. For example, taking the example that the width of the fifth doped sub-region along the second direction is greater than or equal to the width of the sixth doped sub-region along the second direction, the ratio of the width of the first spacer sub-region along the second direction to the width of the fifth doped sub-region along the second direction may be one-fiftieth, one-forty, one-thirtieth, one-twentieth, one-tenth, one-fifth or one-half, etc.

[0105] Exemplarily, the ratio of the area of ​​the first spacer sub-region to the area of ​​the larger one of the fifth doped sub-region and the sixth doped sub-region may be greater than or equal to one-fiftieth and less than or equal to one-half. For example, the area of ​​the fifth doped sub-region is greater than or equal to the area of ​​the sixth doped sub-region. In this case, the ratio of the area of ​​the first spacer sub-region to the area of ​​the fifth doped sub-region may be one-fiftieth, one-forty, one-thirtieth, one-twentieth, one-tenth, one-fifth or one-half, etc. The application principle of the beneficial effect in this case is similar to the application principle of the beneficial effect of the width of the third doped sub-region being greater than the width of the first doped sub-region as described above, and will not be repeated here.

[0106] The specific width ranges of the fifth doped sub-region and the sixth doped sub-region can be determined based on the size of the battery body and the size of the first spacer sub-region mentioned above, as long as they can be applied to the back contact battery provided in the embodiment of the present invention.

[0107] In a second aspect, an embodiment of the present invention provides a photovoltaic module, which includes a back-contact cell provided by the first aspect and various implementations thereof.

[0108] The beneficial effects of the second aspect and its various implementations in the embodiments of the present invention can be analyzed with reference to the beneficial effects of the first aspect and its various implementations, and will not be repeated here.

[0109] In the above description, the technical details of the patterning and etching of each layer are not described in detail. However, those skilled in the art should understand that various technical means can be used to form layers, regions, etc. of desired shapes. In addition, in order to form the same structure, those skilled in the art can also design methods that are not completely the same as the methods described above. In addition, although the various embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage.

[0110] The embodiments of the present invention are described above. However, these embodiments are only for a clearer description and are not intended to limit the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents. Without departing from the scope of the present invention, a person skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present invention.

Claims

1. A back contact battery, characterized in that: include: A battery body, and a first electrode and a second electrode disposed on the battery body; The battery body has a first surface and a second surface opposite to each other; the first surface includes first doping regions and second doping regions that are alternately distributed, and a spacing region between the first doping regions and the second doping regions; The first electrode is disposed on the first doping region and is electrically connected to the first doping region; the second electrode is disposed on the second doping region and is electrically connected to the second doping region; the first electrode and the second electrode both include collector electrodes; the collector electrodes included in the first electrode and the collector electrodes included in the second electrode extend along a first direction and are alternately spaced and distributed along a second direction; the first direction is different from the second direction; Along the second direction, the portion of the spacing region located between two adjacent collector electrodes with opposite polarities is a first spacing sub-region; the portion of the first doped region located below the collector electrode included in the first electrode is a first doped sub-region, and the portion of the second doped region located below the collector electrode included in the second electrode is a second doped sub-region, and the width of the first doped sub-region is greater than or equal to the width of the second doped sub-region; The width of at least one of the first spacer sub-regions along the second direction is greater than the width of at least one of the first doped sub-regions along the second direction; and / or the area of ​​at least one of the first spacer sub-regions is greater than the area of ​​at least one of the first doped sub-regions.

2. The back contact cell according to claim 1, characterized in that: The surface of the spacer area has a suede structure, and the ratio of the total area of ​​all the spacers included in the first surface to the total area of ​​the first surface is greater than 50%.

3. The back contact battery according to claim 1, characterized in that: The ratio of the width of at least one of the first spacer sub-regions to the sum of the widths of the adjacent first doped sub-regions and the second doped sub-regions is P1; 0.5<P1<3.

4. The back contact cell according to claim 1, characterized in that: Along the second direction, the area between the midlines of two adjacent first doped sub-regions is a unit area, or the area between the midlines of two adjacent second doped sub-regions is a unit area; along the second direction, the ratio between the width of a single first spacer sub-region and the width of the unit area is P2, and And / or, in the back contact battery, along the second direction, the ratio of the total number of the collecting electrodes included in the first electrode and the collecting electrodes included in the second electrode to the width of the first spacer region along the second direction is P3, and 0.1≤P3≤15.

5. The back contact cell according to claim 1, characterized in that: The first doped region is an emitter region; The ratio of the cross-sectional area of ​​the first doped sub-region to the cross-sectional area of ​​the second doped sub-region is P4, 0.04<P4<30; or the ratio of the height-to-width ratio of the first doped sub-region to the height-to-width ratio of the second doped sub-region is P5, 0.04<P5<30.

6. The back contact cell according to claim 1, characterized in that: A surface passivation layer is formed on the first surface of the battery body; the collector electrode included in the first electrode penetrates the surface passivation layer and is electrically connected to the first doped region, and the collector electrode included in the second electrode penetrates the surface passivation layer and is electrically connected to the second doped region; A ratio between a width of the first spacer region along the second direction and a thickness of the surface passivation layer is P6, and 1000<P6<5000.

7. The back contact cell according to claim 1, characterized in that: The first electrode and the second electrode also include auxiliary bus electrodes; the auxiliary bus electrodes included in the first electrode and the auxiliary bus electrodes included in the second electrode both extend along the second direction and are alternately spaced and distributed along the first direction; the auxiliary bus electrodes included in the first electrode are electrically connected to at least part of the collector electrodes included in the first electrode, and the auxiliary bus electrodes included in the second electrode are electrically connected to at least part of the collector electrodes included in the second electrode; the collector electrode is disconnected at the intersection with the auxiliary bus electrodes of opposite polarity; along the first direction, the portion of the spacing region located between the collector electrode and the auxiliary bus electrode adjacent to itself and of opposite polarity is the second spacing sub-region; the portion of the first doped region located below the auxiliary bus electrode included in the first electrode is the third doped sub-region, and the portion of the second doped region located below the auxiliary bus electrode included in the second electrode is the fourth doped sub-region; The width of the second spacer sub-region along the first direction is smaller than the width of the larger one of the third doped sub-region and the fourth doped sub-region; or the area of ​​the second spacer sub-region is smaller than the area of ​​the larger one of the third doped sub-region and the fourth doped sub-region.

8. The back contact battery according to claim 7, characterized in that: The width of the third doped sub-region is greater than the width of the first doped sub-region; And / or, the width of the fourth doped sub-region is greater than the width of the second doped sub-region.

9. The back contact cell according to claim 1, characterized in that: The first electrode and the second electrode further include an interconnection structure electrically connected to the collector electrode; a portion of the first doped region located below the interconnection structure included in the first electrode is a fifth doped sub-region, and a portion of the second doped region located below the interconnection structure included in the second electrode is a sixth doped sub-region; The width of the interconnect structure in the second direction is greater than the width of the collector electrode; the width of the fifth doped sub-region is greater than the width of the first doped sub-region; and the width of the sixth doped sub-region is greater than the width of the second doped sub-region.

10. The back contact cell according to claim 1, characterized in that: The first electrode and the second electrode further include an interconnection structure electrically connected to the collector electrode; a portion of the first doped region located below the interconnection structure included in the first electrode is a fifth doped sub-region, and a portion of the second doped region located below the interconnection structure included in the second electrode is a sixth doped sub-region; The ratio of the width of the first spacer sub-region along the second direction to the width of the larger width of the fifth doped sub-region and the sixth doped sub-region along the second direction is greater than or equal to one-fiftieth and less than or equal to one-half; and / or the ratio of the area of ​​the first spacer sub-region to the area of ​​the larger width of the fifth doped sub-region and the sixth doped sub-region is greater than or equal to one-fiftieth and less than or equal to one-half.

11. A photovoltaic module, characterized in that: Comprising a back contact battery as claimed in any one of claims 1 to 10.

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