Back contact battery and photovoltaic module

Abstract

The utility model discloses a back contact cell and a photovoltaic assembly, and relates to the technical field of solar cells. The risk of hot spots is reduced. The back contact cell comprises: a semiconductor substrate having a first surface and a second surface opposite to each other; the first surface is provided with first areas and second areas which are alternately distributed; the first doping part is at least arranged in a part of the first region; the second doping part is at least arranged in a part of the second region; the conduction types of the second doping part and the first doping part are opposite; the first doping part comprises a first sub-doping part arranged in at least a part of the first region and a second sub-doping part arranged in a part of the second region, and the second sub-doping part is electrically connected with the part, arranged in the second region, of the second doping part; and / or the second doping part comprises a third sub-doping part arranged in at least a part of the second region and a fourth sub-doping part arranged in a part of the first region, and the fourth sub-doping part is electrically connected with the part, arranged in the first region, of the first doping part.

Description

Technical Field

[0001] The utility model relates to the technical field of solar cells, in particular to a back-contact battery and a photovoltaic module. Background Technique

[0002] A back-contact battery refers to a battery in which the metal electrodes in the P region and the N region are both located on the back surface of the battery, and there is no metal electrode blocking on the front surface. Compared with the battery with a blocked front surface, the back-contact battery has a higher short-circuit current and a higher photoelectric conversion efficiency, and is one of the technical directions for realizing high-efficiency crystalline silicon batteries at present.

[0003] The hot spot reliability problem of the back-contact battery generally comes from local leakage points. Under the bias voltage, heat will accumulate at the leakage points. When the temperature reaches a certain level, the local adhesive film will melt, peel and burst, and in severe cases, it will catch fire, posing a very big hidden danger to the safety of the component products. One principle for solving the hot spot problem is to completely eliminate the leakage of the battery through the film layer design and insulation process. However, due to the complexity of the back-contact battery, it is extremely difficult to achieve a perfect non-leakage process in mass production. For example, in the back-contact battery, it is necessary to insulate the main grid and the fine grid with the opposite polarity through an insulating adhesive. There will inevitably be process problems such as holes and local thinning in the preparation of the insulating adhesive, and it is easy to be broken down under the long-term large negative pressure, resulting in local leakage and hot spot problems. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a back-contact battery and a photovoltaic module to reduce the risk of hot spots.

[0005] In the first aspect, the utility model provides a back-contact battery, comprising:

[0006] A semiconductor substrate having opposite first and second surfaces; the first surface has alternately distributed first and second regions;

[0007] At least a first doping part provided in at least part of the first region;

[0008] And at least a second doping part provided in at least part of the second region; the conductive type of the second doping part is opposite to that of the first doping part;

[0009] Wherein, the first doping part includes a first sub-doping part provided in at least part of the first region and a second sub-doping part provided in part of the second region, and the second sub-doping part is electrically connected to the part of the second doping part provided in the second region; and / or, the second doping part includes a third sub-doping part provided in at least part of the second region and a fourth sub-doping part provided in part of the first region, and the fourth sub-doping part is electrically connected to the part of the first doping part provided in the first region.

[0010] In the case of adopting the above technical solution, the first doping portion includes two parts. One part, that is, the first sub-doping portion, is disposed in a partial first region of the first surface. The other part, that is, the second sub-doping portion, is disposed in a partial second region, and the second sub-doping portion is electrically connected to the second doping portion located in the second region; and / or, the second doping portion having a conductivity type opposite to that of the first doping portion also includes two parts. One part, that is, the third sub-doping portion, is disposed in a partial second region, and the other part, that is, the fourth sub-doping portion, is disposed in a partial first region, and the fourth sub-doping portion is electrically connected to the first doping portion located in the first region. That is to say, in the first doping portion and the second doping portion with opposite conductivity types, at least one of the regions where the doping portions are located is also provided with a partial other opposite-sex doping portion and is electrically connected to form a leakage current path. When the back-contact battery is shaded, the current provided by other batteries is reversely conducted through the leakage current path of the shaded battery, reducing the hot spot risk and avoiding the reliability risk caused by local heat accumulation due to randomly existing local leakage points in the original back-contact battery. At the same time, the leakage current path provided by the back-contact battery itself has the characteristic of self-bypass. Therefore, it is not necessary to apply a diode in the photovoltaic module, reducing the cost. When the back-contact battery is shaded, it will not cause the loss of the entire string of batteries, improving the power generation capacity.

[0011] In some possible implementation manners, the first doping portion is a first doped semiconductor layer disposed at least on a partial first region, and the second doping portion is a doped semiconductor region disposed at least in a partial second region.

[0012] In the case of adopting the above technical solution, the second doping portion directly forms a doped semiconductor region within the surface of the semiconductor substrate, that is, a partial surface of the semiconductor substrate directly serves as a P region or an N region, and the first doping portion is a film layer structure formed on the surface of the semiconductor substrate, that is, the first doped semiconductor layer. This back-contact battery can form a back-contact battery with different structures for the P region and the N region.

[0013] In some possible implementation manners, in the case where the first doping portion includes a first sub-doping portion and a second sub-doping portion, and the second doping portion includes a third sub-doping portion and a fourth sub-doping portion, the back-contact battery further includes a first electrode electrically connected to the first sub-doping portion and the fourth sub-doping portion, and a second electrode electrically connected to the second sub-doping portion and the third sub-doping portion;

[0014] Or, in the case where the first doping portion includes the first sub-doping portion and the second sub-doping portion, and the second doping portion is only disposed in a partial second region, the first sub-doping portion covers the first region, and the back-contact battery further includes a second electrode electrically connected to the second sub-doping portion and the second doping portion;

[0015] Alternatively, when the first doping portion is only disposed on a part of the first region, and the second doping portion includes the third sub-doping portion and the fourth sub-doping portion, the back contact cell further includes a first electrode electrically connected to the first doping portion and the fourth sub-doping portion.

[0016] In the case of adopting the above technical solution, the first sub-doping portion and the fourth sub-doping portion, both of which are located in the first region, are electrically connected through the first electrode to realize the conduction of the leakage channel in the first region; the third sub-doping portion and the second sub-doping portion, both of which are located in the second region, are electrically connected through the second electrode to realize the conduction of the leakage channel in the second region.

[0017] In some possible implementation manners, the first doping portion is a first doped semiconductor layer disposed at least on a part of the first region, the second doping portion is a second doped semiconductor layer disposed at least on a part of the second region, and the part of the first doped semiconductor layer located on the first region and the part of the second doped semiconductor layer located on the second region are distributed at intervals.

[0018] In the case of adopting the above technical solution, both the first doping portion and the second doping portion are doped film layer structures formed on the surface of the semiconductor substrate, forming the first doped semiconductor layer and the second doped semiconductor layer respectively. The conduction types of the first doped semiconductor layer and the second doped semiconductor layer are different and are respectively one of the P region and the N region. The doped film layer structures on the P region and the N region are distributed at intervals to realize the insulation between the P region and the N region.

[0019] In some possible implementation manners, the first region and the second region are alternately distributed in an interdigitated shape; both the first region and the second region include a plurality of strip regions, and the strip regions included in the first region and the strip regions included in the second region are parallel and alternately distributed;

[0020] When the first doping portion includes the first sub-doping portion and the second sub-doping portion, the orthographic projection of the second sub-doping portion on the first surface is located within the strip region of the second region; and / or when the second doping portion includes the third sub-doping portion and the fourth sub-doping portion, the orthographic projection of the fourth sub-doping portion on the first surface is located within the strip region of the first region.

[0021] In the case of adopting the above technical solution, the first region and the second region can be alternately distributed in an interdigitated pattern. Correspondingly, a fourth sub-doping portion with opposite conductivity is arranged in the strip region of the first region, so that the first doping portion in the strip region of the first region is electrically connected to the fourth sub-doping portion. A second sub-doping portion with opposite conductivity is arranged in the strip region of the second region, so that the second doping portion in the strip region of the second region is electrically connected to the second sub-doping portion, so as to form a leakage channel in the strip region. Since the strip regions are arranged in parallel and alternately, the leakage channels can be more evenly distributed on the back-contact battery, realizing the uniform dispersion of the heat generated after the leakage channels are turned on on the back-contact battery, and further reducing the risk of hot spots caused by local heat accumulation.

[0022] In some possible implementation manners, the total area of the orthographic projection of the second sub-doping portion on the first surface accounts for 0.01% - 1% of the area of the second region; and / or the total area of the orthographic projection of the fourth sub-doping portion on the first surface accounts for 0.01% - 1% of the area of the first region.

[0023] In some possible implementation manners, the sum of the total area of the orthographic projection of the second sub-doping portion on the first surface and the total area of the orthographic projection of the fourth sub-doping portion on the first surface accounts for 0.01% - 1% of the total area of the first region and the second region.

[0024] In the case of adopting the above technical solution, the proportion of the projection area of the second sub-doping portion and / or the second sub-doping portion that forms the leakage channel on the first region and / or the second region is set to 0.01% - 1%, which can not only avoid too small a proportion and being unable to effectively reduce the hot spot risk, but also avoid too large a proportion and affecting the normal power generation efficiency of the back-contact battery.

[0025] In some possible implementation manners, when the orthographic projection of the second sub-doping portion on the first surface is located in the strip region of the second region, along the width direction of the strip region, the edge of the orthographic projection of at least one second sub-doping portion on the first surface has a first gap with the edge of the strip region of the second region, or the edge of the orthographic projection of at least one second sub-doping portion on the first surface coincides with the edge of the strip region of the second region.

[0026] And / or, when the orthographic projection of the fourth sub-doping portion on the first surface is located in the strip region of the first region, along the width direction of the strip region, the edge of the orthographic projection of at least one fourth sub-doping portion on the first surface has a second gap with the edge of the strip region of the first region, or the edge of the orthographic projection of at least one fourth sub-doping portion on the first surface coincides with the edge of the strip region of the first region.

[0027] In the case of adopting the above technical solution, the second sub-doping portion does not exceed the strip area or penetrate the strip area along the width direction of the strip area of the second region. When there is a gap between adjacent strip areas of opposite conductivity types, the second sub-doping portion can penetrate the strip area along the width direction of the strip area, which not only plays a role in forming a leakage channel by electrically connecting the second sub-doping portion with the second doping portion in the strip area of the second region, but also does not affect the insulation of the adjacent strip areas, thereby ensuring normal power generation efficiency. Similarly, the fourth sub-doping portion does not exceed the strip area or penetrate the strip area along the width direction of the strip area of the first region, and has the same beneficial effects as the second sub-doping portion, which will not be repeated.

[0028] In some possible implementations, along the width direction of the strip-shaped region, when there is a first gap between an edge of a positive projection of at least one second sub-doped portion on the first surface and an edge of the strip-shaped region of the second region, the first gap is greater than 0 μm and less than or equal to 200 μm;

[0029] And / or, when there is a second gap between an edge of an orthographic projection of at least one fourth sub-doping portion on the first surface and an edge of the strip region of the first region along the width direction of the strip region, the second gap is greater than 0 μm and less than or equal to 200 μm.

[0030] In the case of adopting the above technical solution, if the first gap between the second sub-doping part and the edge of the strip area of the second region is too large, the size of the second sub-doping part along the width direction of the strip area is small. For the case where the second electrode is required to electrically connect the second sub-doping part with the second doping part, the second electrode may be arranged at the first gap, staggered with the second sub-doping part, and no connection is formed, or the connection area is small, so that the leakage channel cannot be formed, which is not conducive to reducing the risk of hot spots. In addition, if the first gap is too large, the area of the second sub-doping part is small, and the required processing accuracy is high, which increases the process difficulty. Similarly, the reason for selecting the range of the second gap is the same as that of the first gap, which will not be repeated.

[0031] In some possible implementations, when, along the width direction of the strip zone, the edge of the orthographic projection of at least one second sub-doping portion on the first surface has a first gap with the edge of the strip zone of the second region, the two first gaps corresponding to the same second sub-doping portion have different sizes, and the first gaps of different sizes are located on different sides of the two second sub-doping portions adjacent to each other along the width or extension direction of the strip zone; and / or, when, along the width direction of the strip zone, the edge of the orthographic projection of at least one fourth sub-doping portion on the first surface has a second gap with the edge of the strip zone of the first region, the two second gaps corresponding to the same fourth sub-doping portion have different sizes, and the second gaps of different sizes are located on different sides of the two fourth sub-doping portions adjacent to each other along the width or extension direction of the strip zone.

[0032] In the case of adopting the above technical solution, along the width direction of the strip region in the second region, the sizes of the first gaps on both sides of the same second sub-doping portion are different. Among the four first gaps corresponding to two adjacent second sub-doping portions along the width direction of the strip region, the first gaps with different sizes are located on different sides of the two second sub-doping portions. Alternatively, among the four first gaps corresponding to two adjacent second sub-doping portions along the extending direction of the strip region, the first gaps with different sizes are located on different sides of the two second sub-doping portions. With such a setting, the second sub-doping portions arranged along the extending direction of the strip region are not on the same straight line. For the case where the second electrode needs to electrically connect the second sub-doping portion to the second doping portion, the second electrode is arranged on the second doping portion along the extending direction of the strip region. If the second electrode has a misalignment with the second sub-doping portion due to the manufacturing process, the second electrode can at least conductively contact at least half of the second sub-doping portions on the same strip region, and the situation where the second electrode does not contact all the second sub-doping portions will not occur, thereby ensuring the uniform distribution of the leakage channels in the width direction and the extending direction of the strip region and reducing the risk of hot spots. The reason for the setting of the second gap is the same as that of the first gap, and will not be elaborated here.

[0033] In some possible implementation manners, along the distribution direction of the first region and the second region, the length of at least one of the second sub-doping portions and / or at least one of the fourth sub-doping portions is greater than or equal to 50 μm and less than or equal to 500 μm;

[0034] and / or, along the extending direction of the first region or the second region, the width of at least one of the second sub-doping portions and / or at least one of the fourth sub-doping portions is greater than or equal to 50 μm and less than or equal to 500 μm;

[0035] and / or, different second sub-doping portions are evenly distributed;

[0036] and / or, different fourth sub-doping portions are evenly distributed.

[0037] In the case of adopting the above technical solution, if the lengths and widths of the second sub-doping portion and the fourth sub-doping portion are too small, the contact area of the formed leakage channel is small, and the required reverse breakdown voltage is large, which is not conducive to reducing the risk of hot spots. If the lengths and widths are too large, it will affect the normal power generation efficiency of the back-contact battery. Therefore, considering the balance between reducing the risk of hot spots and power generation efficiency, the above range is selected. The uniform distribution of the second sub-doping portion and the fourth sub-doping portion is conducive to the uniform distribution of heat and reduces the risk of hot spots.

[0038] In some possible implementation manners, the conductivity type of the first doping portion is opposite to the conductivity type of the semiconductor substrate; and / or, the first doping portion is an N-type doping region, and the second doping portion is a P-type doping region.

[0039] In a second aspect, the present utility model further provides a photovoltaic module, characterized by comprising the back-contact battery described in any one of the above.

[0040] Since the photovoltaic module includes the back-contact battery described in any one of the above, it has the same beneficial effects as the above back-contact battery, which will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The drawings described herein are used to provide a further understanding of the present utility model and constitute a part of the present utility model. The schematic embodiments of the present utility model and their descriptions are used to explain the present utility model and do not constitute an improper limitation to the present utility model. In the drawings:

[0042] Figure 1 is a schematic diagram of the doping pattern of a back-contact battery provided by an embodiment of the present utility model;

[0043] Figure 2 is a schematic diagram of the doping pattern of another back-contact battery provided by an embodiment of the present utility model;

[0044] Figure 3 is Figure 2 a cross-sectional view taken along line A-A in ;

[0045] Figure 4 is Figure 2 a partially enlarged schematic diagram in ;

[0046] Figure 5 is a schematic diagram of the doping pattern of yet another back-contact battery provided by an embodiment of the present utility model;

[0047] Figure 6 is Figure 5 a cross-sectional view taken along line B-B in ;

[0048] Figure 7 is Figure 5 a partially enlarged schematic diagram in.

[0049] Reference numerals:

[0050] 1 is the first doping part, 11 is the first sub-doping part, 12 is the second sub-doping part, 2 is the second doping part, 21 is the third sub-doping part, 22 is the fourth sub-doping part, and 3 is the semiconductor substrate. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0051] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present utility model clearer, the present utility model will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0052] 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.

[0053] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, "a plurality of" means two or more, unless otherwise specifically defined. "Several" means one or more, unless otherwise specifically defined.

[0054] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation of the present utility model.

[0055] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", and "coupled" 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 directly connected or indirectly connected through an intermediate medium, and can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0056] As Figures 1-7 shown, an embodiment of the present utility model provides a back contact battery, including a semiconductor substrate 3, a first doping portion 1, and a second doping portion 2; wherein, the semiconductor substrate 3 has opposite first and second surfaces; the first surface has alternately distributed first and second regions; the first doping portion 1 is disposed at least in part of the first region, the second doping portion 2 is disposed at least in part of the second region, and the conductive types of the first doping portion 1 and the second doping portion 2 are opposite.

[0057] Among them, as Figures 1-4As shown, the first doping portion 1 includes a first sub-doping portion 11 disposed in at least a part of the first region and a second sub-doping portion 12 disposed in a part of the second region. The second sub-doping portion 12 is electrically connected to a part of the second doping portion 2 disposed in the second region. That is, in the second region, the second doping portion 2 and the second sub-doping portion 12 with opposite conduction types are simultaneously disposed and electrically connected in the second region; and / or, as Figures 5-7 shown, the second doping portion 2 includes a third sub-doping portion 21 disposed in at least a part of the second region and a fourth sub-doping portion 22 disposed in a part of the first region. The fourth sub-doping portion 22 is electrically connected to a part of the first doping portion 1 disposed in the first region. That is, in the first region, the first doping portion 1 and the fourth sub-doping portion 22 with opposite conduction types are simultaneously disposed and electrically connected in the first region.

[0058] In the case of adopting the above technical solution, the first doping portion 1 includes two parts. The main part, that is, the first sub-doping portion 11, is disposed in the first region, and the other smaller part, that is, the second sub-doping portion 12, is disposed in a part of the second region, and the second sub-doping portion 12 is electrically connected to the second doping portion 2 located in the second region; and / or, the second doping portion 2 with a conduction type opposite to that of the first doping portion 1 also includes two parts. The main part, that is, the third sub-doping portion 21, is disposed in the second region, and the other smaller part, that is, the fourth sub-doping portion 22, is disposed in a part of the first region, and the fourth sub-doping portion 22 is electrically connected to the first doping portion 1 located in the first region. That is to say, in the first doping portion 1 and the second doping portion 2 with opposite conduction types, at least one doping portion's region is also provided with a part of the other doping portion with opposite conductivity and is electrically connected to form a leakage channel in the first region and / or the second region. When the back-contact battery is shaded, the current provided by other batteries is reversely conducted through the leakage channel of the shaded battery, reducing the hot-spot risk and avoiding the reliability risk caused by local heat accumulation due to randomly existing local leakage points in the original back-contact battery. At the same time, the leakage channel set in the back-contact battery itself has the characteristic of self-bypass. Therefore, it is not necessary to apply a diode in the photovoltaic module, reducing the cost. When the back-contact battery is shaded, it will not cause the loss of the entire string of batteries and improves the power generation capacity.

[0059] It should be noted that the fourth sub-doping portion 22, which is of opposite conductivity and electrically connected to the first doping portion 1, and the second sub-doping portion 12, which is of opposite conductivity and electrically connected to the second doping portion 2, are both structures with relatively small regions and can be in the shape of a block, a short strip, etc., so as to form a leakage channel in a local small region in the first region and / or the second region, reducing the hot-spot risk when the back-contact battery is shaded while ensuring the normal power generation efficiency when the back-contact battery is not shaded.

[0060] In some embodiments, the first doping portion 1 is a first doped semiconductor layer disposed at least on a part of the first region, and the second doping portion 2 is a doped semiconductor region disposed at least within a part of the second region.

[0061] In the case of adopting the above technical solution, the second doping portion 2 directly forms a doped semiconductor region within the surface of the semiconductor substrate 3, that is, a part of the surface of the semiconductor substrate 3 directly serves as a P region or an N region, and the first doping portion 1 is a film layer structure formed on the surface of the semiconductor substrate 3, that is, the first doped semiconductor layer. This back contact battery can form a back contact battery with different structures for the P region and the N region.

[0062] Exemplarily, taking the first doping portion 1 as an N-type doping region, the second doping portion 2 as a P-type doping region, and the semiconductor substrate 3 as a P-type substrate as an example for illustration, when the first doping portion 1 includes a first doped semiconductor layer, the first doped semiconductor layer may include a doped polysilicon layer, and a tunneling oxide layer is disposed between the doped polysilicon layer and the semiconductor substrate 3 to form a tunneling passivation contact structure. When the second doping portion 2 includes a doped semiconductor region, the doped semiconductor region may be a part of the surface on the second region of the P-type substrate, and an aluminum electrode is disposed on this part of the surface to form a P+ back field. This back contact battery is a hybrid back contact battery combined with a tunneling passivation contact structure and an aluminum back field structure.

[0063] Corresponding to this hybrid back contact battery, as Figures 1-4 shown, when the first doping portion 1 includes a first sub-doping portion 11 and a second sub-doping portion 12, a whole layer of tunneling oxide layer and doped polysilicon layer may be formed on the entire first surface of the P-type substrate first, and then, the tunneling oxide layer and the doped polysilicon layer on the entire first region and a part of the second region are retained, and the tunneling oxide layer and the doped polysilicon layer on the remaining parts of the second region are removed to expose the P-type substrate surface of the second region, obtaining the first sub-doping portion 11 retained in the first region and the second sub-doping portion 12 retained in the second region, and forming the second doping portion 2 (i.e., the doped semiconductor region) located in the second region. Within the second region, the doped polysilicon layer serving as the second sub-doping portion 12 is electrically connected to the P-type substrate surface of the second region to form a leakage channel.

[0064] Similarly, as Figures 5-7As shown, when the second doping portion 2 includes a third sub-doping portion 21 and a fourth sub-doping portion 22, a whole layer of tunneling oxide layer and doped polysilicon layer can be formed on the entire first surface of the P-type substrate. After that, the tunneling oxide layer and doped polysilicon layer at the remaining positions in the first region except for the position corresponding to the fourth sub-doping portion 22 are retained, and the tunneling oxide layer and doped polysilicon layer in the entire second region and the tunneling oxide layer and doped polysilicon layer corresponding to the fourth sub-doping portion in the first region are removed, exposing the P-type substrate surface in the second region and a part of the first region, obtaining the exposed third sub-doping portion 21 and fourth sub-doping portion 22 (i.e., doped semiconductor regions). In the first region, the exposed P-type substrate surface serving as the fourth sub-doping portion 22 is electrically connected to the doped polysilicon layer in the first region, forming a leakage channel.

[0065] Of course, the first doping portion can also be a P-type doping region, the second doping portion can also be an N-type doping region, and the semiconductor substrate can be an N-type substrate. The doping structure is similar to the above and will not be elaborated.

[0066] Furthermore, in the case where the first doping portion 1 is a first doped semiconductor layer disposed at least in a part of the first region and the second doping portion 2 is a doped semiconductor region disposed at least in a part of the second region, if the first doping portion 1 includes a first sub-doping portion 11 and a second sub-doping portion 12, and the second doping portion 2 includes a third sub-doping portion 21 and a fourth sub-doping portion 22, the back contact battery further includes a first electrode electrically connected to the first sub-doping portion 11 and the fourth sub-doping portion 22, and a second electrode electrically connected to the second sub-doping portion 12 and the third sub-doping portion 21. With such a setting, the first sub-doping portion 11 and the fourth sub-doping portion 22 both located in the first region are electrically connected through the first electrode, realizing the conduction of the leakage channel in the first region. At the same time, the second sub-doping portion 12 and the third sub-doping portion 21 both located in the second region are electrically connected through the second electrode, realizing the conduction of the leakage channel in the second region.

[0067] As Figures 1-4 shown, if the first doping portion 1 includes a first sub-doping portion 11 and a second sub-doping portion 12, and the second doping portion 2 is only disposed in a part of the second region, and the first sub-doping portion 11 covers the first region, the back contact battery further includes a second electrode electrically connected to the second sub-doping portion 12 and the second doping portion 2. With such a setting, the second sub-doping portion 12 and the second doping portion 2 both located in the second region are electrically connected through the second electrode, realizing the conduction of the leakage channel in the second region.

[0068] As Figures 5-7As shown in the figure, if the first doping portion 1 is only disposed on a part of the first region, and the second doping portion 2 includes a third sub-doping portion 21 and a fourth sub-doping portion 22, the back contact battery further includes a first electrode electrically connected to the first doping portion 1 and the fourth sub-doping portion 22. With such a setting, the first doping portion 1 and the fourth sub-doping portion 22, both of which are located in the first region, are electrically connected through the first electrode, realizing the conduction of the leakage channel within the first region.

[0069] In some possible implementation manners, the first doping portion 1 is a first doped semiconductor layer disposed at least on a part of the first region, the second doping portion is a second doped semiconductor layer disposed at least on a part of the second region, and the part of the first doped semiconductor layer located in the first region and the part of the second doped semiconductor layer located in the second region are spaced apart.

[0070] In the case of adopting the above technical solution, both the first doping portion 1 and the second doping portion 2 are doped film layer structures formed on the surface of the semiconductor substrate 3, forming the first doped semiconductor layer and the second doped semiconductor layer respectively. The conduction types of the first doped semiconductor layer and the second doped semiconductor layer are different, and they are respectively one of the P region and the N region. The doped film layer structures on the P region and the N region are spaced apart to realize the insulation between the P region and the N region.

[0071] Exemplarily, taking the first doping portion 1 as an N-type doping region and the second doping portion 2 as a P-type doping region as an example for illustration, when the first doping portion 1 includes a first doped semiconductor layer, the first doped semiconductor layer may include an N-type doped polysilicon layer, and a first tunneling oxide layer is disposed between the N-type doped polysilicon layer and the semiconductor substrate 3 to form a tunneling passivation contact structure. When the second doping portion 2 includes a second doped semiconductor layer, the second doped semiconductor layer may include a P-type doped polysilicon layer, and a second tunneling oxide layer is disposed between the P-type doped polysilicon layer and the semiconductor substrate 3, also forming a tunneling passivation contact structure. This back contact battery is a tunneling passivation contact back contact battery in which both the P region and the N region are tunneling passivation contact structures.

[0072] For the corresponding tunnel passivated contact back contact cell, when the first doped portion 1 includes a first sub-doped portion 11 and a second sub-doped portion 12, a whole layer of first tunnel oxide layer and N-type doped polysilicon layer can be formed on the entire first surface of the semiconductor substrate 3 first. Then, the first tunnel oxide layer and N-type doped polysilicon layer on the entire first region and part of the second region are retained, and the first tunnel oxide layer and N-type doped polysilicon layer on the remaining parts of the second region are removed to expose the surface of the semiconductor substrate 3 in the second region, obtaining the first sub-doped portion 11 retained in the first region and the second sub-doped portion 12 retained in the second region. Then, a second tunnel oxide layer and P-type doped polysilicon layer are formed at positions in the second region other than the second sub-doped portion 12, obtaining the second doped portion 2 in the second region. In the second region, the N-type doped polysilicon layer serving as the second sub-doped portion 12 is electrically connected to the P-type doped polysilicon layer in the second region to form a leakage channel.

[0073] Similarly, when the second doped portion 2 includes a third sub-doped portion 21 and a fourth sub-doped portion 22, a whole layer of first tunnel oxide layer and N-type doped polysilicon layer can be formed on the entire first surface of the semiconductor substrate 3 first. Then, the first tunnel oxide layer and N-type doped polysilicon layer on the remaining positions in the first region other than the position corresponding to the fourth sub-doped portion are retained, and the first tunnel oxide layer and N-type doped polysilicon layer of the whole second region and the first tunnel oxide layer and N-type doped polysilicon layer corresponding to the fourth sub-doped portion in the first region are removed to expose the surface of the semiconductor substrate 3 in the second region and part of the first region, obtaining the first doped portion 1 in the first region. Then, a second tunnel oxide layer and P-type doped polysilicon layer are formed on the surface of the semiconductor substrate 3 in the second region and the exposed part of the semiconductor substrate 3 in the first region, obtaining the third sub-doped portion 21 in the second region and the fourth sub-doped portion 22 in part of the first region. In the first region, the P-type doped polysilicon layer serving as the fourth sub-doped portion 22 is electrically connected to the N-type doped polysilicon layer in the first region to form a leakage channel.

[0074] Certainly, the first doped portion 1 can also be a P-type doped region, the second doped portion 2 can also be an N-type doped region, and the semiconductor substrate 3 can be an N-type substrate. The doping structure is similar to the above and will not be elaborated.

[0075] Such as Figures 1-3As shown, in some possible implementation manners, the first region and the second region are alternately distributed in an interdigitated manner; both the first region and the second region include a plurality of strip regions, the strip regions included in the first region and the strip regions included in the second region are parallel and alternately distributed; alternatively, on the basis of including strip regions, the first region and the second region may further both include at least one connection region; each connection region is electrically connected to the corresponding strip region having the same conductivity type as itself; the extending direction of the connection region is different from the extending direction of the strip region; when the first doping portion 1 includes a first sub-doping portion 11 and a second sub-doping portion 12, correspondingly, the first sub-doping portion 11 is located in the strip region of the first region, the extending direction of the first sub-doping portion 11 is the same as the extending direction of this strip region, and the orthographic projection of the second sub-doping portion 12 on the first surface is located in the strip region of the second region; and / or, when the second doping portion 2 includes a third sub-doping portion 21 and a fourth sub-doping portion 22, correspondingly, the third sub-doping portion 21 is located in the strip region of the second region, the extending direction of the third sub-doping portion 21 is the same as the extending direction of this strip region, and the orthographic projection of the fourth sub-doping portion 22 on the first surface is located in the strip region of the first region.

[0076] In the case of adopting the above technical solution, the first region and the second region may be alternately distributed in an interdigitated manner. Correspondingly, a fourth sub-doping portion 22 with opposite conductivity is arranged in the strip region of the first region, so that the first doping portion 1 in the strip region of the first region is electrically connected to the fourth sub-doping portion 22, and a second sub-doping portion 12 with opposite conductivity is arranged in the strip region of the second region, so that the second doping portion 2 in the strip region of the second region is electrically connected to the second sub-doping portion 12, so as to form a leakage channel in the strip region. Since the strip regions are arranged in parallel and alternately, therefore, the leakage channels can be relatively evenly distributed on the back-contact battery, realizing the uniform dispersion of the heat generated after the leakage channels are conducted on the back-contact battery, and further reducing the hot spot risk caused by local heat accumulation.

[0077] In some embodiments, the position where the orthographic projection of the second sub-doping portion 12 on the first surface is located in the corresponding strip region is at any position along the extending direction of the corresponding strip region.

[0078] Similarly, the position where the orthographic projection of the fourth sub-doping portion 22 on the first surface is located in the corresponding strip region is at any position along the extending direction of the corresponding strip region.

[0079] As long as the effective reduction of the hot spot risk can be achieved, the second sub-doping portion 12 and the fourth sub-doping portion 22 may be evenly distributed on the strip region along the extending direction of the strip region, which is beneficial to the uniform dispersion of the heat generated after the leakage channels are conducted on the back-contact battery, and further reduces the hot spot risk caused by local heat accumulation.

[0080] In some embodiments, the position of the positive projection of at least one second sub-doping portion 12 on the first surface within the corresponding strip region is located in the region from one-tenth to nine-tenths of the corresponding strip region along its own extension direction. By way of example, the position of the second sub-doping portion 12 is located at the 1 / 10 position, 1 / 5 position, 1 / 3 position, 1 / 2 position, 2 / 3 position, 3 / 5 position, 4 / 5 position, 9 / 10 position, etc. along the extension direction of the strip region.

[0081] In some embodiments, the position of the positive projection of at least one fourth sub-doping portion 22 on the first surface within the corresponding strip region is located in the region from one-tenth to nine-tenths of the corresponding strip region along its own extension direction. By way of example, the position of the fourth sub-doping portion 22 is located at the 1 / 10 position, 1 / 5 position, 1 / 3 position, 1 / 2 position, 2 / 3 position, 3 / 5 position, 4 / 5 position, 9 / 10 position, etc. along the extension direction of the strip region.

[0082] In the case of adopting the above technical solution, by setting the leakage channel in the region from one-tenth to nine-tenths of the strip region along its own extension direction, the carrier transmission path can be effectively reduced, the transmission resistance can be reduced, the heat generation here can be reduced, and further the risk of hot spots caused by local heat accumulation can be reduced, which is beneficial to the uniform dispersion of the heat generated after the leakage channel is turned on in the back-contact battery.

[0083] In some embodiments, when only the second sub-doping portion 12 is provided in the second region, the total area of the positive projection of the second sub-doping portion 12 on the first surface accounts for 0.01% - 1% of the area of the second region. For example, the area ratio can be 0.01%, 0.1%, 0.2%, 0.5%, 0.7%, 1%, etc.; and / or, when only the fourth sub-doping portion 22 is provided in the first region, the total area of the positive projection of the fourth sub-doping portion 22 on the first surface accounts for 0.01% - 1% of the area of the first region. For example, the area ratio can be 0.01%, 0.1%, 0.2%, 0.5%, 0.7%, 1%, etc.; or, when the second sub-doping portion 12 is provided in the second region and the fourth sub-doping portion 22 is provided in the first region, the sum of the total area of the positive projection of the second sub-doping portion 12 on the first surface and the total area of the positive projection of the fourth sub-doping portion 22 on the first surface accounts for 0.01% - 1% of the total area of the first region and the second region. For example, the area ratio can be 0.01%, 0.1%, 0.2%, 0.5%, 0.7%, 1%, etc.

[0084] In the case of adopting the above technical solution, by setting the ratio of the projection area of the second sub-doping portion 12 and / or the second sub-doping portion 22 forming the leakage channel on the first region and / or the second region to 0.01% - 1%, it can not only avoid the ratio being too small to effectively reduce the risk of hot spots, but also avoid the ratio being too large to affect the normal power generation efficiency of the back-contact battery.

[0085] As shown Figure 3 in the figure, in some embodiments, when the positive projection of the second sub-doping portion 12 on the first surface is located within the strip-shaped area of the second region, along the width direction of the strip-shaped area, there is a first gap D1 between the edge of the positive projection of at least one second sub-doping portion 12 on the first surface and the edge of the strip-shaped area of the second region, or, as Figure 1 shown in the figure, the edge of the positive projection of at least one second sub-doping portion 12 on the first surface coincides with the edge of the strip-shaped area of the second region.

[0086] As shown Figure 6 in the figure, when the positive projection of the fourth sub-doping portion 22 on the first surface is located within the strip-shaped area of the first region, along the width direction of the strip-shaped area, there is a second gap D2 between the edge of the positive projection of at least one fourth sub-doping portion 22 on the first surface and the edge of the strip-shaped area of the first region, or, the edge of the positive projection of at least one fourth sub-doping portion 22 on the first surface coincides with the edge of the strip-shaped area of the first region.

[0087] In the case of adopting the above technical solution, the second sub-doping portion 12 does not extend beyond or penetrates through the strip-shaped area along the width direction of the strip-shaped area of the second region. When there is a gap between adjacent strip-shaped areas with opposite conduction types, the second sub-doping portion 12 can penetrate through the strip-shaped area along the width direction of the strip-shaped area, which not only plays a role in forming a leakage channel by electrically connecting the second sub-doping portion 12 with the second doping portion 2 within the strip-shaped area of the second region, but also does not affect the insulation of adjacent strip-shaped areas, ensuring normal power generation efficiency. Similarly, the fourth sub-doping portion 22 does not extend beyond or penetrates through the strip-shaped area along the width direction of the strip-shaped area of the first region, and has the same beneficial effects as the second sub-doping portion 12, which will not be elaborated here.

[0088] Exemplarily, when there is a first gap D1 between the edge of the positive projection of at least one second sub-doping portion 12 on the first surface and the edge of the strip-shaped area of the second region along the width direction of the strip-shaped area, the first gap D1 is greater than 0 μm and less than or equal to 200 μm. Specifically, D1 can be 1 μm, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 100 μm, 150 μm, 200 μm, etc. Further, the first gap D1 is greater than or equal to 10 μm and less than or equal to 50 μm.

[0089] Exemplarily, in the case where there is a second gap D2 between the orthographic projection edge of at least one fourth sub-doping portion 22 on the first surface and the edge of the strip-shaped area of the first region along the width direction of the strip-shaped area, the second gap D2 is greater than or equal to 0 μm and less than or equal to 200 μm, and specifically D2 may be 1 μm, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 100 μm, 150 μm, 200 μm, etc. Further, the second gap D2 is greater than or equal to 10 μm and less than or equal to 50 μm.

[0090] In the case of adopting the above technical solution, if the first gap D1 between the second sub-doping part 12 and the edge of the strip area of the second region is too large, the size of the second sub-doping part 12 along the width direction of the strip area is small. For the case where the second electrode is required to electrically connect the second sub-doping part 12 with the second doping part 2, the second electrode may be arranged at the first gap D1, staggered with the second sub-doping part 12, and no connection is formed, or the connection area is small, so a leakage channel with good contact cannot be formed, which is not conducive to reducing the risk of hot spots; and if the first gap D1 is too large, the area of the second sub-doping part 12 is small, and the required processing accuracy is high, which increases the process difficulty. Therefore, considering the reduction of the risk of hot spots and the process difficulty, the first gap D1 is selected to be greater than or equal to 0μm and less than or equal to 200μm. Similarly, the range selection of the second gap D2 is the same as the range selection of the first gap D1, which will not be repeated.

[0091] like Figure 1 , Figure 2 , Figure 4 , Figure 5 and Figure 7 As shown, in some embodiments, when there is a first gap D1 between the orthographic projection edge of at least one second sub-doping portion 12 on the first surface and the edge of the strip-shaped region of the second region along the width direction of the strip-shaped region, the sizes of the two first gaps D1 corresponding to the same second sub-doping portion 12 are different, and the first gaps D1 of different sizes are located on different sides of the two second sub-doping portions 12 adjacent to each other along the width or extension direction of the strip-shaped region. For example, Figure 4The description is made with respect to the shown orientation. For two adjacent second sub-doping portions 12 along the width direction, among the two first gaps D1 of different sizes corresponding to the upper second sub-doping portion 12, the first gap D1 with a larger spacing is located above the upper second sub-doping portion 12, and the first gap D1 with a smaller spacing is located below the upper second sub-doping portion 12. Then, among the two first gaps D1 of different sizes corresponding to the lower second sub-doping portion 12, the first gap D1 with a larger spacing is located below the lower second sub-doping portion 12, and the first gap D1 with a smaller spacing is located above the lower second sub-doping portion 12. Similarly, for two adjacent second sub-doping portions 12 along the extending direction of the strip region, for the first gap D1 with a larger spacing corresponding to the left second sub-doping portion 12, it is located above, and the first gap D1 with a smaller spacing is located below. Then, for the first gap D1 with a larger spacing corresponding to the right second sub-doping portion 12, it is located below, and the first gap D1 with a smaller spacing is located above.

[0092] Similarly, in the case where along the width direction of the strip region, at least one fourth sub-doping portion 22 has a second gap D2 between the edge of its orthographic projection on the first surface and the edge of the strip region of the first region, the two second gaps D2 corresponding to the same fourth sub-doping portion 22 are of different sizes, and the second gaps D2 of different sizes are located on different sides of two adjacent fourth sub-doping portions 22 along the width or extending direction of the strip region. The setting manner of the second gap D2 is the same as that of the first gap D1, and will not be elaborated here.

[0093] In the case of adopting the above technical solution, the second sub-doping portions 12 arranged along the extending direction of the strip region are not on the same straight line. For the case where a second electrode is required to electrically connect the second sub-doping portions 12 to the second doping portion 2, the second electrode is arranged on the second doping portion 2 along the extending direction of the strip region. If the second electrode has a deviation in the width direction in alignment with the second sub-doping portions 12 due to the manufacturing process, the second electrode can at least conductively contact at least half of the second sub-doping portions 12 on the same strip region, and there will be no situation where the second electrode is not in contact with all the second sub-doping portions 12, thus ensuring the uniform distribution of the leakage channels in the width direction and the extending direction of the strip region and reducing the risk of hot spots. The reason and beneficial effect of setting the second gap D2 are the same as those of the first gap D1, and will not be elaborated.

[0094] As Figure 3 and Figure 4As shown, further, along the distribution direction of the first region and the second region, the length L1 of at least one second sub-doping portion 12 is greater than or equal to 50 μm and less than or equal to 500 μm. For example, L1 can be 50 μm, 100 μm, 150 μm, 200 μm, 300 μm, 400 μm, 500 μm, etc. And / or, the length L2 of at least one fourth sub-doping portion 22 is greater than or equal to 50 μm and less than or equal to 500 μm. For example, L2 can be 50 μm, 100 μm, 150 μm, 200 μm, 300 μm, 400 μm, 500 μm, etc.

[0095] In another example, along the extension direction of the first region or the second region, the width W1 of at least one second sub-doping portion 12 is greater than 0 μm and less than or equal to 500 μm. For example, W1 can be 51 μm, 100 μm, 150 μm, 200 μm, 300 μm, 400 μm, 500 μm, etc. And / or, the width W2 of at least one fourth sub-doping portion 22 is greater than 0 μm and less than or equal to 500 μm. For example, W1 can be 51 μm, 100 μm, 150 μm, 200 μm, 300 μm, 400 μm, 500 μm, etc.

[0096] In the case of adopting the above technical solution, if the lengths and widths of the second sub-doping portion 12 and the fourth sub-doping portion 22 are too small, the contact area of the formed leakage channel is small, and the required reverse breakdown voltage is large, which is not conducive to reducing the hot spot risk. If the lengths and widths are too large, the required reverse breakdown voltage is small, which affects the normal power generation efficiency of the back-contact battery. Therefore, considering the balance between reducing the hot spot risk and the power generation efficiency, the above range is selected.

[0097] In some embodiments, when the first doping portion 1 includes the second sub-doping portion 12, different second sub-doping portions 12 are uniformly distributed in the first plane. When the second doping portion 2 includes the fourth sub-doping portion 22, different fourth sub-doping portions 22 are uniformly distributed in the first plane. The uniform distribution of the second sub-doping portion 12 and the fourth sub-doping portion 22 is beneficial to the uniform distribution of heat and reduces the hot spot risk.

[0098] Based on the back-contact battery described in any of the above embodiments, the embodiment of the present invention further provides a photovoltaic module, including the back-contact battery described in any of the above embodiments.

[0099] Since the photovoltaic module includes the back-contact battery described in any of the above embodiments, it has the same beneficial effects as the above back-contact battery, which will not be elaborated here.

[0100] The above are only the specific embodiments of the present utility model, but the protection scope of the present utility model is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present utility model can easily think of changes or substitutions, which should all be covered within the protection scope of the present utility model. Therefore, the protection scope of the present utility model shall be subject to the protection scope of the said claims.

Claims

1. A back-contact battery, characterized in that, Comprising: A semiconductor substrate having opposite first and second surfaces; The first surface has alternating first and second regions; A first doping portion disposed at least in part of the first region; And a second doping portion disposed at least in part of the second region; the conductivity type of the second doping portion is opposite to that of the first doping portion; Wherein, the first doping portion includes a first sub-doping portion disposed at least in part of the first region and a second sub-doping portion disposed in part of the second region, and the second sub-doping portion is electrically connected to the portion of the second doping portion disposed in the second region; and / or, the second doping portion includes a third sub-doping portion disposed at least in part of the second region and a fourth sub-doping portion disposed in part of the first region, and the fourth sub-doping portion is electrically connected to the portion of the first doping portion disposed in the first region.

2. The back-contact battery according to claim 1, characterized in that, The first doping portion is a first doped semiconductor layer disposed at least in part of the first region, and the second doping portion is a doped semiconductor region disposed at least in part of the second region.

3. The back-contact battery according to claim 2, wherein, In the case where the first doping portion includes the first sub-doping portion and the second sub-doping portion, and the second doping portion includes the third sub-doping portion and the fourth sub-doping portion, the back-contact battery further includes a first electrode electrically connected to the first sub-doping portion and the fourth sub-doping portion, and a second electrode electrically connected to the second sub-doping portion and the third sub-doping portion; Or, in the case where the first doping portion includes the first sub-doping portion and the second sub-doping portion, and the second doping portion is disposed only in part of the second region, the first sub-doping portion covers the first region, and the back-contact battery further includes a second electrode electrically connected to the second sub-doping portion and the second doping portion; Or, in the case where the first doping portion is disposed only in part of the first region, and the second doping portion includes the third sub-doping portion and the fourth sub-doping portion, the back-contact battery further includes a first electrode electrically connected to the first doping portion and the fourth sub-doping portion.

4. The back-contact battery according to claim 1, characterized in that, The first doping portion is a first doped semiconductor layer disposed at least in part of the first region, and the second doping portion is a second doped semiconductor layer disposed at least in part of the second region, and the portion of the first doped semiconductor layer located in the first region and the portion of the second doped semiconductor layer located in the second region are spaced apart.

5. The back contact battery according to any one of claims 1 to 4, characterized in that, The first region and the second region are alternately distributed in a finger-like pattern; both the first region and the second region include a plurality of strip-shaped regions, and the strip-shaped regions included in the first region and the strip-shaped regions included in the second region are parallel and alternately distributed; When the first doping portion includes the first sub-doping portion and the second sub-doping portion, the positive projection of the second sub-doping portion on the first surface is located within the strip-shaped area of the second region; and / or, when the second doping portion includes the third sub-doping portion and the fourth sub-doping portion, the positive projection of the fourth sub-doping portion on the first surface is located within the strip-shaped area of the first region.

6. The back contact battery according to claim 5, characterized in that, The total area of the positive projection of the second sub-doping portion on the first surface accounts for 0.01% - 1% of the area of the second region; and / or the total area of the positive projection of the fourth sub-doping portion on the first surface accounts for 0.01% - 1% of the area of the first region.

7. The back contact battery according to claim 5, characterized in that, When the positive projection of the second sub-doping portion on the first surface is located within the strip-shaped area of the second region, along the width direction of the strip-shaped area, at least one edge of the positive projection of the second sub-doping portion on the first surface has a first gap with the edge of the strip-shaped area of the second region, or at least one edge of the positive projection of the second sub-doping portion on the first surface coincides with the edge of the strip-shaped area of the second region; and / or, when the positive projection of the fourth sub-doping portion on the first surface is located within the strip-shaped area of the first region, along the width direction of the strip-shaped area, at least one edge of the positive projection of the fourth sub-doping portion on the first surface has a second gap with the edge of the strip-shaped area of the first region, or at least one edge of the positive projection of the fourth sub-doping portion on the first surface coincides with the edge of the strip-shaped area of the first region.

8. The back-contact battery according to claim 7, characterized in that, When at least one edge of the positive projection of the second sub-doping portion on the first surface has a first gap with the edge of the strip-shaped area of the second region along the width direction of the strip-shaped area, the first gap is greater than 0μm and less than or equal to 200μm; and / or, when at least one edge of the positive projection of the fourth sub-doping portion on the first surface has a second gap with the edge of the strip-shaped area of the first region along the width direction of the strip-shaped area, the second gap is greater than 0μm and less than or equal to 200μm.

9. The back-contact battery according to claim 7, wherein, When at least one edge of the positive projection of the second sub-doping portion on the first surface has a first gap with the edge of the strip-shaped area of the second region along the width direction of the strip-shaped area, the sizes of the two first gaps corresponding to the same second sub-doping portion are different, and the different-sized first gaps are located on different sides of two adjacent second sub-doping portions along the width or extension direction of the strip-shaped area; and / or, when at least one edge of the positive projection of the fourth sub-doping portion on the first surface has a second gap with the edge of the strip-shaped area of the first region along the width direction of the strip-shaped area, the sizes of the two second gaps corresponding to the same fourth sub-doping portion are different, and the different-sized second gaps are located on different sides of two adjacent fourth sub-doping portions along the width or extension direction of the strip-shaped area.

10. The back-contact battery according to claim 1, wherein In the distribution direction of the first region and the second region, the length of at least one of the second sub-doping portions and / or at least one of the fourth sub-doping portions is greater than or equal to 50 μm and less than or equal to 500 μm; And / or, in the extending direction of the first region or the second region, the width of at least one of the second sub-doping portions and / or at least one of the fourth sub-doping portions is greater than 0 μm and less than or equal to 500 μm; And / or, different second sub-doping portions are uniformly distributed; And / or, different fourth sub-doping portions are uniformly distributed.

11. The back contact battery according to claim 1, characterized in that, The conductivity type of the first doping portion is opposite to that of the semiconductor substrate; And / or, the first doping portion is an N-type doping region, and the second doping portion is a P-type doping region.

12. A photovoltaic module, characterized in that, Comprising the back contact battery according to any one of claims 1 to 11.

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