Battery structure, battery assembly and photovoltaic system

Abstract

The invention discloses a battery structure, a battery assembly and a photovoltaic system. The battery structure comprises a substrate, a plurality of N-type doped regions and a plurality of P-type doped regions, wherein the N-type doped regions and the P-type doped regions are arranged on the first side of the substrate; the N-type doped regions and the P-type doped regions are arranged alternately; an isolation groove is arranged between the adjacent N-type doped region and the P-type doped region, and the isolation groove is used for isolating the N-type doped region and the P-type doped region; the P-type doped region comprises a first central region and first edge regions, the first edge regions are located on the two sides of the first central region, the first edge regions are provided with pits, and the vertical projection of the first edge regions on the substrate is not overlapped with the vertical projection of the isolation grooves on the substrate. The reliability of the battery structure can be improved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more particularly to a battery structure, battery module, and photovoltaic system. Background Technology

[0002] A solar cell is a thin photovoltaic semiconductor wafer that generates electricity directly using sunlight. It is also known as a "solar chip" or "photovoltaic cell". As long as the illuminance meets certain conditions, it can instantly output voltage and generate current when there is a circuit.

[0003] In related technologies, to prevent leakage current between the first and second doped regions in back-contact solar cells, isolation trenches are typically used to separate the first and second doped regions. However, the fabrication of these isolation trenches introduces a risk of microcracks into the cell, affecting its reliability. Summary of the Invention

[0004] This invention provides a battery structure, battery module, and photovoltaic system that can improve the reliability of the battery structure.

[0005] According to one aspect of the present invention, a battery structure is provided, comprising:

[0006] A substrate, and a plurality of N-type doped regions and a plurality of P-type doped regions disposed on a first side of the substrate; the N-type doped regions and the P-type doped regions are arranged alternately;

[0007] An isolation trench is provided between adjacent N-type doped regions and P-type doped regions to isolate the N-type doped regions and P-type doped regions;

[0008] The P-type doped region includes a first central region and a first edge region. The first edge region is located on both sides of the first central region. The first edge region has a pit. The vertical projection of the first edge region on the substrate does not overlap with the vertical projection of the isolation trench on the substrate.

[0009] Based on the above embodiments, optionally, the area of ​​the first central region is less than or equal to 90% of the area of ​​the P-type doped region.

[0010] Based on the above embodiments, optionally, the N-type doped region includes a second central region and a second edge region, the second edge region is located on both sides of the second central region, the second edge region does not have pits, and the vertical projection of the second edge region on the substrate does not overlap with the vertical projection of the isolation trench on the substrate.

[0011] Based on the above embodiments, optionally, the N-type doped region includes a second central region and a second edge region, the second edge region is located on both sides of the second central region, the second edge region has a pit, and the vertical projection of the second edge region on the substrate does not overlap with the vertical projection of the isolation trench on the substrate.

[0012] The number of pits in the second edge region is less than the number of pits in the first edge region.

[0013] Based on the above embodiments, optionally, the area of ​​the pit in the first edge region accounts for 5%-20% of the area of ​​the first edge region;

[0014] The area of ​​the pit in the second edge region accounts for 0.1%-2% of the area of ​​the second edge region.

[0015] Based on the above embodiments, optionally, the area of ​​the first edge region accounts for 5%-10% of the total area of ​​the P-type doped region;

[0016] The area of ​​the second edge region accounts for 5%-10% of the total area of ​​the N-type doped region.

[0017] Based on the above embodiments, optionally, the pit in the first edge region extends from the surface of the N-type doped region away from the substrate into the interior of the substrate;

[0018] The pits in the second edge region extend from the surface of the P-type doped region away from the substrate into the interior of the substrate.

[0019] Based on the above embodiments, optionally, the pit includes a first sidewall, a bottom, and a second sidewall connected in sequence;

[0020] The lengths of the first and second sidewalls range from 0.1 micrometers to 5 micrometers;

[0021] The bottom length ranges from 0.1 micrometers to 2 micrometers;

[0022] The angle between the first sidewall and the bottom is 125-135 degrees; the angle between the second sidewall and the bottom is 125-135 degrees.

[0023] Based on the above embodiments, optionally, the density of pits in the first edge region is greater than or equal to 10 pits per 100 square micrometers;

[0024] The density of pits in the second edge region is less than 5 per 100 square micrometers.

[0025] Based on the above embodiments, optionally, the P-type doped region includes a first extension, which is located on the side of the first edge region away from the first center region; the first extension extends toward the isolation trench and is located above the isolation trench;

[0026] The N-type doped region includes a second extension located on the side of the second edge region away from the second center region; the second extension extends toward the isolation trench and is located above the isolation trench.

[0027] Based on the above embodiments, optionally, the length of the first extension ranges from 0.3 micrometers to 3 micrometers, and the thickness of the first extension ranges from 20 nanometers to 300 nanometers;

[0028] The length of the second extension ranges from 0.1 micrometers to 2 micrometers, and the thickness of the second extension ranges from 10 nanometers to 200 nanometers.

[0029] Based on the above embodiments, optionally, the first extension has a first hole, and the first hole penetrates the first extension;

[0030] The second extension has a second hole that penetrates the second extension;

[0031] The number of second holes is less than the number of first holes.

[0032] Based on the above embodiments, optionally, the edge of the N-type doped region adjacent to the isolation trench includes a plurality of first arcs, at least some of which have different curvatures; the edge length of the N-type doped region adjacent to the isolation trench is the total length of the plurality of first arcs;

[0033] The edge of the P-type doped region adjacent to the isolation trench includes multiple second arcs, at least some of which have different curvatures; the edge length of the P-type doped region adjacent to the isolation trench is the total length of the multiple second arcs.

[0034] The number of first arcs is less than the number of second arcs;

[0035] The total length of the multiple first arcs is less than the total length of the multiple second arcs.

[0036] According to another aspect of the present invention, a battery assembly is provided, including the battery structure described in any embodiment of the present invention.

[0037] According to another aspect of the present invention, a photovoltaic system is provided, including the battery module described in any embodiment of the present invention.

[0038] The battery structure provided by this invention includes: a substrate, and multiple N-type doped regions and multiple P-type doped regions disposed on a first side of the substrate; the N-type and P-type doped regions are arranged alternately; an isolation trench is disposed between adjacent N-type and P-type doped regions to isolate them; the P-type doped region includes a first central region and a first edge region, the first edge region being located on both sides of the first central region, the first edge region having a pit, and the vertical projection of the first edge region on the substrate not overlapping with the vertical projection of the isolation trench on the substrate. When a passivation layer is subsequently formed, the passivation layer can fill the pit, making the structure of the passivation layer and the P-type doped region more stable, thereby improving the reliability of the battery structure.

[0039] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of a battery structure provided according to an embodiment of the present invention.

[0042] Figure 2 This is an electron microscope schematic diagram of a P-type doped layer according to an embodiment of the present invention.

[0043] Figure 3 This is an electron microscope schematic diagram of an N-type doped layer according to an embodiment of the present invention.

[0044] Figure 4 This is an electron microscope schematic diagram of another N-type doped layer provided according to an embodiment of the present invention. Detailed Implementation

[0045] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0046] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0047] This invention provides a battery structure. Figure 1 This is a schematic diagram of a battery structure provided according to an embodiment of the present invention. Figure 2 This is an electron microscope schematic diagram of a p-type doped layer according to an embodiment of the present invention, with reference to... Figure 1 and Figure 2 The battery structure includes:

[0048] The substrate 10 includes a plurality of N-type doped regions 11 and a plurality of P-type doped regions 12 disposed on a first side of the substrate 10. The N-type doped regions 11 and P-type doped regions 12 are arranged alternately. An isolation trench 30 is disposed between adjacent N-type doped regions 11 and P-type doped regions 12, and the isolation trench 30 is used to isolate the N-type doped regions 11 and P-type doped regions 12. The P-type doped region 12 includes a first central region 01 and a first edge region 02. The first edge region 02 is located on both sides of the first central region 01. The first edge region 02 has a pit 21. The vertical projection of the first edge region 02 on the substrate 10 does not overlap with the vertical projection of the isolation trench 30 on the substrate 10.

[0049] The battery structure can be a solar cell, which can be a back-contact solar cell. The substrate 10 is the foundation of the battery structure; the substrate 10 includes two opposing surfaces, namely a light-facing surface and a back-facing surface. The light-facing surface directly faces sunlight and has no electrodes to block it, thus maximizing the light absorption area and reducing shading loss, significantly improving the photoelectric conversion efficiency of the battery. The back-facing surface is the other side; the first side of the substrate 10 is the back-facing surface. The material of the substrate 10 can be monocrystalline silicon, polycrystalline silicon, or silicon wafers similar to monocrystalline silicon. The substrate 10 can be an n-type substrate or a p-type substrate. The substrate 10 forms a pn junction with the N-type doped region 11 or the P-type doped region 12, generating a photovoltaic effect. When light shines on the solar cell, photons can excite electrons to jump from the valence band to the conduction band, forming electron-hole pairs. These charge carriers separate at the pn junction due to the electric field, generating current.

[0050] During the fabrication of the device, a mask layer is needed to form 11 N-type doped regions and 12 P-type doped regions. When removing the mask layer, a high-energy laser is used to open the stacked structure. The stacked structure is placed below the laser, and the laser beam is focused on the doped region to ablate it. The high energy of the laser beam is focused at the location of the isolation trench 30, which can make the isolation trench 30 uniformly and smoothly distributed. However, the diffraction characteristics of the laser will cause the first edge region 02 of the P-type doped region 12 to have a pit 21. When the passivation layer is formed later, the passivation layer can fill the pit 21, making the structure of the passivation layer and the P-type doped region 12 more stable, thereby improving the reliability of the battery structure.

[0051] The battery structure provided by the embodiment of the present invention includes: a substrate 10, and a plurality of N-type doped regions 11 and a plurality of P-type doped regions 12 disposed on a first side of the substrate 10; the N-type doped regions 11 and P-type doped regions 12 are arranged alternately; an isolation trench 30 is disposed between adjacent N-type doped regions 11 and P-type doped regions 12, the isolation trench 30 is used to isolate the N-type doped regions 11 and P-type doped regions 12; the P-type doped region 12 includes a first central region 01 and a first edge region 02, the first edge region 02 is located on both sides of the first central region 01, the first edge region 02 has a pit 21, and the vertical projection of the first edge region 02 on the substrate 10 does not overlap with the vertical projection of the isolation trench 30 on the substrate 10. When a passivation layer is subsequently formed, the passivation layer can fill the pit 21, making the structure of the passivation layer and the P-type doped region 12 more stable, thereby improving the reliability of the battery structure.

[0052] Based on the above embodiments, optionally, refer to Figure 1 and Figure 2 The area of ​​the first central region 01 is less than or equal to 90% of the area of ​​the P-type doped region 12.

[0053] The P-type doped region also includes a first extension 03, and the total area of ​​the first extension 03 and the first edge region 02 is greater than or equal to 100% of the area of ​​the P-type doped region 12. Setting the area of ​​the first central region 01 to be less than or equal to 90% of the area of ​​the P-type doped region 12 can enable the P-type doped region 12 to have sufficient carrier collection capacity and improve the photoelectric conversion efficiency of the battery structure.

[0054] Based on the above embodiments, optionally, Figure 3 This is an electron microscope schematic diagram of an N-type doped layer according to an embodiment of the present invention, with reference to... Figure 1 and Figure 3 The N-type doped region 11 includes a second central region 04 and a second edge region 05. The second edge region 05 is located on both sides of the second central region 04. The second edge region 05 does not have a pit 21. The vertical projection of the second edge region 05 on the substrate 10 does not overlap with the vertical projection of the isolation trench 30 on the substrate 10.

[0055] The second edge region 05 of the N-type doped region 11 does not have a pit 21, which allows for a larger contact area between the N-type doped region 11 and the substrate 10. This improves the carrier collection capability of the N-type doped region 11, resulting in higher photoelectric conversion efficiency of the battery structure. Furthermore, the absence of a pit 21 in the N-type doped region 11 makes the edge of the second edge region 05 adjacent to the isolation trench 30 smooth, which improves the internal stability of the N-type doped region 11 structure and makes the device structure more reliable.

[0056] Based on the above embodiments, optionally, refer to Figure 1The N-type doped region 11 includes a second central region 04 and a second edge region 05. The second edge region 05 is located on both sides of the second central region 04. The second edge region 05 has pits 21. The vertical projection of the second edge region 05 on the substrate 10 does not overlap with the vertical projection of the isolation trench 30 on the substrate 10. The number of pits 21 in the second edge region 05 is less than the number of pits 21 in the first edge region 02.

[0057] The number of pits 21 in the second edge region 05 is less than the number of pits 21 in the first edge region 02, which makes the edge of the second edge region 05 adjacent to the isolation trench 30 smooth, resulting in better internal stability and higher reliability of the N-type doped region 11 structure.

[0058] Based on the above embodiments, optionally, refer to Figures 1-3 The area of ​​the pit 21 in the first edge region 02 accounts for 5%-20% of the area of ​​the first edge region 02; the area of ​​the pit 21 in the second edge region 05 accounts for 0.1%-2% of the area of ​​the second edge region 05.

[0059] Among them, the area of ​​the pit 21 in the first edge region 02 accounts for 5%-20% of the area of ​​the first edge region 02; the area of ​​the pit 21 in the second edge region 05 accounts for 0.1%-2% of the area of ​​the second edge region 05. It can be understood that within the same unit area, the first edge region 02 has a larger number of pits and is more dense, while the second edge region 05 has a smaller number of pits and is more sparse, which makes the edge of the N-type doped region 11 smoother and the internal structure of the N-type doped region 11 more stable.

[0060] Based on the above embodiments, optionally, refer to Figure 1 The area of ​​the first edge region 02 accounts for 5%-10% of the total area of ​​the P-type doped region 12; the area of ​​the second edge region 05 accounts for 5%-10% of the total area of ​​the N-type doped region 11.

[0061] The pits 21 are located within the first edge region 02 and the second edge region 05. The area of ​​the first edge region 02 accounts for 5%-10% of the total area of ​​the P-type doped region 12, and the area of ​​the second edge region 05 accounts for 5%-10% of the total area of ​​the N-type doped region 11. This ensures that the pits 21 are located in both the N-type doped region 11 and the P-type doped region 12, thereby guaranteeing the carrier collection capability of the central regions of the N-type doped region 11 and the P-type doped region 12 and improving the photoelectric conversion efficiency of the battery structure.

[0062] Based on the above embodiments, optionally, refer to Figure 1 The pit 21 of the first edge region 02 extends from the surface of the N-type doped region 11 away from the substrate 10 into the interior of the substrate 10; the pit 21 of the second edge region 05 extends from the surface of the P-type doped region 12 away from the substrate 10 into the interior of the substrate 10.

[0063] in, Figure 4 This is an electron microscope schematic diagram of another N-type doped layer provided according to an embodiment of the present invention, with reference to... Figure 4 The cross-sectional shape of the pit can be trapezoidal, rectangular, etc. When performing laser film opening, for example, an ultraviolet laser can be used. The diffraction characteristics of the laser will form a pit 21. The energy of the diffracted laser will cause the pit to penetrate the N-type doped region 11 and the P-type doped region 12 into the substrate 10.

[0064] Based on the above embodiments, optionally, refer to Figure 4 The pit 21 includes a first sidewall C1, a bottom C2, and a second sidewall C3 connected in sequence; the lengths of the first sidewall C1 and the second sidewall C3 range from 0.1 micrometers to 5 micrometers; the length of the bottom C2 ranges from 0.1 micrometers to 2 micrometers; the angle A between the first sidewall C1 and the bottom C2 is 125 degrees to 135 degrees; and the angle B between the second sidewall C3 and the bottom C2 is 125 degrees to 135 degrees.

[0065] The lengths of the first sidewall C1, the bottom C2, and the second sidewall C3, as well as the angle A between the first sidewall C1 and the bottom C2 and the angle B between the second sidewall C3 and the bottom C2, can be determined by the laser irradiation time and power. Different processing times can create different sizes and angles of the pit 21.

[0066] Based on the above embodiments, optionally, the density of pits in the first edge region is greater than or equal to 10 pits per 100 square micrometers; and the density of pits in the second edge region is less than 5 pits per 100 square micrometers.

[0067] Specifically, when the unit area is 100 square micrometers, the number of pits in the first edge region is greater than or equal to 10, the number of pits in the second edge region is less than 5, the number of pits in the second edge region of the N-type doped region 11 is less than the number of pits in the first edge region of the P-type doped region 12, the edge of the N-type doped region 11 is smoother than the edge of the P-type doped region 12, the structure of the N-type doped region 11 is more stable, and the reliability is higher.

[0068] Based on the above embodiments, optionally, refer to Figure 1 The P-type doped region 12 includes a first extension 03, which is located on the side of the first edge region 02 away from the first center region 01; the first extension 03 extends toward the isolation trench 30 and is located above the isolation trench 30; the N-type doped region 11 includes a second extension 06, which is located on the side of the second edge region 05 away from the second center region 04; the second extension 06 extends toward the isolation trench 30 and is located above the isolation trench 30.

[0069] The P-type doped region 12 includes a first extension 03, and the N-type doped region 11 includes a second extension 06. When the substrate 10 is etched, the substrate 10 is etched rapidly, while the etching rate of the portion of the substrate 10 near the N-type doped region 11 and the P-type doped region 12 decreases, so that the N-type doped region 11 forms the second extension 06 and the P-type doped region 12 forms the first extension 03. The first extension 03 and the second extension 06 are both located above the isolation trench 30, that is, the vertical projections of the first extension 03 and the second extension 06 on the substrate 10 are both located within the isolation trench 30.

[0070] Based on the above embodiments, optionally, refer to Figure 1 The length of the first extension 03 ranges from 0.3 micrometers to 3 micrometers, and the thickness of the first extension 03 ranges from 20 nanometers to 300 nanometers; the length of the second extension 06 ranges from 0.1 micrometers to 2 micrometers, and the thickness of the second extension 06 ranges from 10 nanometers to 200 nanometers.

[0071] The lengths of all extensions are perpendicular to the direction pointing from the substrate 10 towards the N-type doped region, and the thicknesses are also perpendicular to the direction pointing from the substrate 10 towards the N-type doped region. The length of the first extension 03 ranges from 0.3 micrometers to 3 micrometers, and the length of the second extension 06 ranges from 0.1 micrometers to 2 micrometers. This design prevents the extensions from becoming too long, which could lead to structural instability and breakage. The thickness of the first extension 03 ranges from 20 nanometers to 300 nanometers, and the thickness of the second extension 06 ranges from 10 nanometers to 200 nanometers. The thickness of the first extension 03 is the same as the thickness of the P-type doped region 12, and the thickness of the second extension 06 is the same as the thickness of the N-type doped region 11. This design ensures that the thicknesses of the N-type doped region 11 and the P-type doped region 12 are neither too thin, which would result in insufficient carrier collection, nor would it lead to increased carrier transport losses later on.

[0072] Based on the above embodiments, optionally, refer to Figures 1-3 The first extension 03 has a first hole 22, which penetrates the first extension 03; the second extension 06 has a second hole 23, which penetrates the second extension 06; the number of second holes 23 is less than the number of first holes 22.

[0073] The first extension 03 is located at the outermost edge of the P-type doped region 12, and the second extension 06 is located at the outermost edge of the N-type doped region 11. During laser film opening, the diffraction characteristics of the laser will cause the first extension 03 of the P-type doped region 12 to have a first hole 22, and the second extension 06 of the N-type doped region 11 to have a second hole 23. The number of second holes 23 is less than the number of first holes 22, which makes the edge of the N-type doped region 11 adjacent to the isolation trench 30 smooth, and makes the internal stability of the structure of the N-type doped region 11 better and the reliability higher.

[0074] Based on the above embodiments, optionally, refer to Figure 2 and Figure 3 The edge of the N-type doped region 11 adjacent to the isolation trench 30 includes a plurality of first arcs, at least some of which have different curvatures; the edge length of the N-type doped region 11 adjacent to the isolation trench 30 is the total length of the plurality of first arcs; the edge of the P-type doped region 12 adjacent to the isolation trench 30 includes a plurality of second arcs, at least some of which have different curvatures; the edge length of the P-type doped region 12 adjacent to the isolation trench 30 is the total length of the plurality of second arcs; the number of first arcs is less than the number of second arcs; the total length of the plurality of first arcs is less than the total length of the plurality of second arcs.

[0075] Among them, the edge of the N-type doped region 11 adjacent to the isolation trench 30 is smooth, the number of first arcs is small, and the curvature varies little; the edge of the P-type doped region 12 adjacent to the isolation trench 30 is rough, the number of second arcs with different curvatures is large, and the curvature varies much; the number of first arcs is less than the number of second arcs; the total length of multiple first arcs is less than the total length of multiple second arcs, which further illustrates that the edge of the N-type doped region 11 adjacent to the isolation trench 30 is smooth, and the edge of the P-type doped region 12 adjacent to the isolation trench 30 is rough.

[0076] This invention also provides a battery assembly, including the battery structure described in the above embodiments.

[0077] A battery module may include multiple battery structures, each of which is a solar cell. Multiple solar cells in a battery module can be connected in series to form a battery string. The battery strings can be connected in series, in parallel, or in a series-parallel combination to achieve current output. For example, the connection between individual battery cells can be achieved by welding ribbons, or the connection between individual battery strings can be achieved by busbars.

[0078] The battery module may also include a metal frame, a backsheet, photovoltaic glass, and an encapsulating film. The encapsulating film can be filled between the light-facing side of the solar cell and the photovoltaic glass, the back-facing side and the backsheet, and adjacent cells. As a filler, it can be a transparent colloid with good light transmittance and aging resistance; for example, EVA film or POE film can be used, and the choice is based on the specific circumstances and is not limited here. The photovoltaic glass can cover the encapsulating film on the light-facing side of the solar cell. The photovoltaic glass can be ultra-clear glass, which has high light transmittance, high transparency, and superior physical, mechanical, and optical properties. For example, the light transmittance of ultra-clear glass can reach over 92%, which can protect the solar cell while minimizing the impact on its efficiency. Simultaneously, the encapsulating film can bond the photovoltaic glass and the solar cell together, and its presence provides sealing, insulation, waterproofing, and moisture protection for the solar cell.

[0079] The backsheet can be attached to the encapsulating film on the back side of the solar cell. The backsheet protects and supports the solar cell, providing reliable insulation, water resistance, and aging resistance. Multiple backsheet options are available, typically including tempered glass, acrylic glass, and aluminum alloy TPT composite encapsulating film, etc. The specific choice depends on the specific circumstances and is not limited here. The backsheet, solar cell, encapsulating film, and photovoltaic glass can be mounted on a metal frame. The metal frame serves as the main external support structure for the entire battery module, providing stable support and installation. For example, the battery module can be installed at the desired location using the metal frame.

[0080] The battery assembly of this invention belongs to the same concept as the battery structure described in the above embodiments of this application and has corresponding beneficial effects. For technical details not covered in this embodiment, please refer to the battery structure described in any embodiment of this application.

[0081] This invention also provides a photovoltaic system, including the battery module described in the above embodiments.

[0082] Photovoltaic systems can be applied in photovoltaic power plants, such as ground-mounted, rooftop, and floating power plants, as well as in equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it's understandable that the application scenarios of photovoltaic systems are not limited to these; that is, photovoltaic systems can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation network as an example, a photovoltaic system can include photovoltaic arrays, combiner boxes, and inverters. A photovoltaic array can be a combination of multiple battery modules; for example, multiple battery modules can form multiple photovoltaic arrays. The photovoltaic arrays are connected to combiner boxes, which collect the current generated by the photovoltaic arrays. The collected current flows through an inverter and is converted into AC power required by the mains grid before being connected to the mains grid to achieve solar power supply.

[0083] The beneficial effects of the photovoltaic system in this embodiment of the invention are equivalent to the beneficial effects of the battery module described above, and will not be repeated here.

[0084] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0085] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A battery structure, characterized in that, include: A substrate, and a plurality of N-type doped regions and a plurality of P-type doped regions disposed on a first side of the substrate; The N-type doped regions and the P-type doped regions are arranged alternately; An isolation trench is provided between adjacent N-type doped regions and P-type doped regions, the isolation trench being used to isolate the N-type doped regions and P-type doped regions; The P-type doped region includes a first central region and a first edge region. The first edge region is located on both sides of the first central region. The first edge region has a pit. The vertical projection of the first edge region on the substrate does not overlap with the vertical projection of the isolation trench on the substrate.

2. The battery structure according to claim 1, characterized in that: The area of ​​the first central region is less than or equal to 90% of the area of ​​the P-type doped region.

3. The battery structure according to claim 1, characterized in that: The N-type doped region includes a second central region and a second edge region. The second edge region is located on both sides of the second central region. The second edge region does not have pits. The vertical projection of the second edge region on the substrate does not overlap with the vertical projection of the isolation trench on the substrate.

4. The battery structure according to claim 1, characterized in that: The N-type doped region includes a second central region and a second edge region. The second edge region is located on both sides of the second central region. The second edge region has a pit. The vertical projection of the second edge region on the substrate does not overlap with the vertical projection of the isolation trench on the substrate. The number of pits in the second edge region is less than the number of pits in the first edge region.

5. The battery structure according to claim 4, characterized in that: The area of ​​the pit in the first edge region accounts for 5%-20% of the area of ​​the first edge region; The area of ​​the pit in the second edge region accounts for 0.1%-2% of the area of ​​the second edge region.

6. The battery structure according to claim 4, characterized in that: The area of ​​the first edge region accounts for 5%-10% of the total area of ​​the P-type doped region; The area of ​​the second edge region accounts for 5%-10% of the total area of ​​the N-type doped region.

7. The battery structure according to claim 4, characterized in that: The pit in the first edge region extends from the surface of the N-type doped region away from the substrate into the interior of the substrate; The pit in the second edge region extends from the surface of the P-type doped region away from the substrate into the interior of the substrate.

8. The battery structure according to claim 1, characterized in that: The pit includes a first sidewall, a bottom, and a second sidewall connected in sequence; The lengths of the first sidewall and the second sidewall range from 0.1 micrometers to 5 micrometers; The bottom length ranges from 0.1 micrometers to 2 micrometers; The angle between the first sidewall and the bottom is 125-135 degrees; the angle between the second sidewall and the bottom is 125-135 degrees.

9. The battery structure according to claim 3, characterized in that: The density of pits in the first edge region is greater than or equal to 10 per 100 square micrometers; The density of pits in the second edge region is less than 5 per 100 square micrometers.

10. The battery structure according to claim 3, characterized in that: The P-type doped region includes a first extension, which is located on the side of the first edge region away from the first center region; the first extension extends toward the isolation trench and is located above the isolation trench. The N-type doped region includes a second extension located on the side of the second edge region away from the second center region; the second extension extends toward the isolation trench and is located above the isolation trench.

11. The battery structure according to claim 10, characterized in that: The length of the first extension ranges from 0.3 micrometers to 3 micrometers, and the thickness of the first extension ranges from 20 nanometers to 300 nanometers. The length of the second extension ranges from 0.1 micrometers to 2 micrometers, and the thickness of the second extension ranges from 10 nanometers to 200 nanometers.

12. The battery structure according to claim 10, characterized in that: The first extension has a first hole that penetrates the first extension; The second extension has a second hole that penetrates the second extension; The number of the second hole is less than the number of the first hole.

13. The battery structure according to claim 10, characterized in that: The edge of the N-type doped region adjacent to the isolation trench includes a plurality of first arcs, at least some of which have different curvatures; the length of the edge of the N-type doped region adjacent to the isolation trench is the total length of the plurality of first arcs. The edge of the P-type doped region adjacent to the isolation trench includes a plurality of second arcs, at least some of which have different curvatures; the length of the edge of the P-type doped region adjacent to the isolation trench is the total length of the plurality of second arcs; The number of the first arcs is less than the number of the second arcs; The total length of the plurality of first arcs is less than the total length of the plurality of second arcs.

14. A battery assembly, characterized in that, Includes the battery structure described in any one of claims 1-13.

15. A photovoltaic system, characterized in that, Includes the battery assembly as described in claim 14.

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