Photovoltaic cell, module and system

Abstract

Provided are a photovoltaic cell, module and system. The photovoltaic cell comprises: a silicon substrate (100); a plurality of p-type doped regions (110) and a plurality of n-type doped regions (120) that are alternately arranged in sequence along a first direction on the back surface of the silicon substrate (100); p-type fingers (310); n-type fingers (320); and isolation regions (130) each arranged between a corresponding p-type doped region (110) and a corresponding n-type doped region (120) that are adjacent to each other. In the first direction, a ratio C1 of the width of the isolation regions (130) to the width of the n-type doped regions (120) is 2 / 9≤C1≤3.

Description

Photovoltaic cells, modules, and systems

[0001] Cross Reference to Related Applications

[0002] The present disclosure claims priority to the Chinese patent application No. 202411337048.1, filed on September 24, 2024, entitled “Back contact solar cell, photovoltaic module and photovoltaic system”, the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure belongs to the technical field of back contact solar cells, and particularly relates to a back contact solar cell, a photovoltaic module and a photovoltaic system. BACKGROUND

[0004] The back contact solar cell has no main grid lines on the front surface, and the positive electrode and the negative electrode are both arranged on the back surface of the cell, thereby reducing the light blocking and effectively increasing the short-circuit current of the cell, so that the energy conversion efficiency of the solar cell is improved, and the application prospect is wide.

[0005] The back contact cell forms alternating p-type doped regions and n-type doped regions on the back surface. Since the polarities of the p-type doped regions and the n-type doped regions are different, an isolation region needs to be arranged between the p-type doped regions and the n-type doped regions for isolation. The isolation region is provided with a textured structure, and the textured structure increases the reflection of light. However, since the width of the isolation region is narrow, the area of the textured structure inside the isolation region is small, the light reflectivity is low, and the photoelectric conversion efficiency of the cell is affected. SUMMARY

[0006] The present disclosure provides a back contact solar cell, which aims to solve the problem of low photoelectric conversion efficiency of the existing back contact solar cell.

[0007] The present disclosure is implemented in this way. A back contact solar cell includes:

[0008] A silicon substrate, a back surface of the substrate is provided with a plurality of p-type doped regions and a plurality of n-type doped regions which are alternately arranged in a first direction;

[0009] A p-type fine grid electrically connected to the p-type doped region;

[0010] An n-type fine grid electrically connected to the n-type doped region; and

[0011] An isolation region arranged between adjacent p-type doped regions and n-type doped regions;

[0012] In the first direction, the ratio of the width of the isolation region to the width of the n-type doped region is C1,

[0013] In some embodiments, a ratio C1 of the width of the isolation region to the width of the n-type doped region is

[0014] In some embodiments, the width of the isolation region is 200 microns to 300 microns.

[0015] In some embodiments, the width of the n-type doped region is greater than or equal to the width of the p-type doped region.

[0016] In some embodiments, a ratio D1 of the width of the n-type doped region to the width of the p-type doped region is 1≤D1≤9.

[0017] In some embodiments, the ratio D1 of the width of the n-type doped region to the width of the p-type doped region is 1.5≤D1≤4.

[0018] In some embodiments, the width of the p-type doped region is 100 microns to 900 microns.

[0019] In some embodiments, the sum of the widths of the single p-type doped region, the single n-type doped region, and the single isolation region is 400 microns to 9.3 millimeters.

[0020] In some embodiments, the sum of the widths of the single p-type doped region, the single n-type doped region, and the single isolation region is 450 microns to 4.8 millimeters.

[0021] In some embodiments, the sheet resistance of the p-type doped region is greater than the sheet resistance of the n-type doped region.

[0022] In some embodiments, the sheet resistance of the p-type doped region is 1.5 times to 10 times the sheet resistance of the n-type doped region.

[0023] In some embodiments, the back contact solar cell further comprises a passivation layer disposed on a side of the n-type doped region and the p-type doped region opposite the silicon substrate, and the passivation layer is provided with a first window and a second window, the p-type fine grid at least partially extends into the first window and contacts the p-type doped region, and the n-type fine grid at least partially extends into the second window and contacts the n-type doped region.

[0024] In some embodiments, a distance between the p-type doped region or the n-type doped region adjacent to the edge of the silicon substrate and the edge of the silicon substrate is less than a distance between the p-type doped region and the n-type doped region located in a middle region of the silicon substrate.

[0025] In some embodiments, a main grid p-type doped region is further included, the main grid p-type doped region is cross-connected with the p-type doped region, the n-type doped region is electrically isolated from the main grid p-type doped region, and a distance of the electrical isolation between the n-type doped region and the main grid p-type doped region is less than the width of the isolation region.

[0026] In some embodiments, the isolation region comprises a first region, a second region, and a trench;

[0027] The first region is adjacent to the p-type doped region, the second region is adjacent to the n-type doped region, and the trench is between the first region and the second region.

[0028] In some embodiments, the bottom of the trench is textured.

[0029] In some embodiments, the first region has a polished surface.

[0030] In some embodiments, the second region has a polished surface.

[0031] In some embodiments, the first region is doped with a p-type dopant.

[0032] In some embodiments, the second region is doped with an n-type dopant.

[0033] In some embodiments, the p-type doped region and the n-type doped region each comprises any one of polysilicon, amorphous silicon, microcrystalline silicon, and monocrystalline silicon.

[0034] In a second aspect, the present application also provides a photovoltaic module comprising the back contact solar cell as described above.

[0035] In a third aspect, the present application also provides a photovoltaic system comprising the photovoltaic module as described above.

[0036] The back contact solar cell provided by the present application comprises a silicon substrate, a p-type fine grid electrically connected to the p-type doped region, an n-type fine grid electrically connected to the n-type doped region, and an isolation region disposed between adjacent p-type doped regions and n-type doped regions. Through the above arrangement, the width of the isolation region is increased, thereby increasing the area of the textured structure in the isolation region, improving the light reflection efficiency, and improving the photoelectric conversion efficiency of the solar cell. BRIEF DESCRIPTION OF DRAWINGS

[0037] FIG. 1 is a structural schematic diagram of one embodiment of the back contact solar cell provided by the present application;

[0038] FIG. 2 is a distribution schematic diagram of the doped regions of one embodiment of the back contact solar cell provided by the present application;

[0039] FIG. 3 is a partial structural schematic diagram of one embodiment of the back contact solar cell provided by the present application.

[0040] Reference numerals: 100, silicon substrate; 110, p-type doped region; 120, n-type doped region; 130, isolation region; 131, first region; 132, second region; 133, trench; 200, passivation layer; 310, p-type fine gate; 320, n-type fine gate. DETAILED DESCRIPTION

[0041] In order to make the objects, technical solutions and advantages of the present disclosure clearer, the present disclosure will be further described in detail below with reference to the drawings and embodiments. Examples of the embodiments are shown in the drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present disclosure, and cannot be understood as a limitation of the present disclosure. In addition, it should be understood that the specific embodiments described herein are only used to explain the present disclosure and cannot be used to limit the present disclosure.

[0042] In the description of the present disclosure, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom" and the like indicate the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present disclosure and simplify the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present disclosure.

[0043] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more features. In the description of the present disclosure, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0044] In the description of the present disclosure, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present disclosure can be understood according to the specific circumstances.

[0045] In the present disclosure, unless explicitly specified and limited, "on" or "under" of a first feature to a second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, "on", "above" and "over" of a first feature to a second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the first feature is horizontally higher than the second feature. "Under", "below" and "underneath" of a first feature to a second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the first feature is horizontally lower than the second feature.

[0046] The following disclosure provides many different embodiments or examples for implementing different structures of the present disclosure. For simplicity of the present disclosure, the components and settings of particular examples are described in the following. Of course, they are only examples and the purpose is not to limit the present disclosure. In addition, the present disclosure can repeatedly refer to numerical values and / or reference letters in different examples, and such repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present disclosure provides examples of various specific processes and materials, but those of ordinary skill in the art can realize the application of other processes and / or the use of other materials.

[0047] The back contact solar cell provided by the present application comprises a silicon substrate, a back surface of the silicon substrate is provided with a plurality of p-type doped regions and a plurality of n-type doped regions which are arranged alternately in sequence along a first direction; a p-type fine grid electrically connected with the p-type doped regions; an n-type fine grid electrically connected with the n-type doped regions; and an isolation region provided between adjacent p-type doped regions and n-type doped regions, in the first direction, a ratio C1 of a width of the isolation region to a width of the n-type doped region is Through the above setting, the width of the isolation region is increased, and then the area of the textured structure in the isolation region is increased, the light reflection efficiency is improved, and the photoelectric conversion efficiency of the solar cell is improved.

[0048] Embodiment one

[0049] As shown in FIGS. 1 to 3, one embodiment of the present application provides a back contact solar cell, comprising:

[0050] A silicon substrate 100, a back surface of the silicon substrate 100 is provided with a plurality of p-type doped regions 110 and a plurality of n-type doped regions 120 which are arranged alternately in sequence along a first direction;

[0051] A p-type fine grid 310 electrically connected with the p-type doped regions 110;

[0052] An n-type fine grid 320 electrically connected with the n-type doped regions 120; and

[0053] The isolation region 130 is arranged between the adjacent p-type doped region 110 and the n-type doped region 120;

[0054] In the first direction, the ratio of the width of the isolation region 130 to the width of the n-type doped region 120 is C1,

[0055] In implementation, the solar cell is also called solar photovoltaic (abbreviation: PV), which is a kind of photovoltaic semiconductor wafer that directly generates electricity by using sunlight, also known as "solar chip" or "photocell". As long as the solar cell is irradiated by light with a certain illuminance, it can output voltage and generate current in the case of a loop.

[0056] The back contact solar cell refers to that the electrode grid lines are all located on the back surface of the cell, thereby reducing or eliminating the shading loss of the front grid lines and improving the cell efficiency.

[0057] In implementation, the silicon substrate 100 can be an N-type silicon wafer or a P-type silicon wafer, wherein the N-type silicon wafer is obtained by adding a 5-valence element (such as phosphorus or arsenic) into the silicon raw material, and these 5-valence elements provide additional free electrons; the P-type silicon wafer is obtained by adding a 3-valence element (such as boron or gallium) into the silicon raw material, and these 3-valence elements control the diffusion of electron holes, which will not be described herein.

[0058] The silicon substrate 100 has a front surface and a back surface, wherein the front surface of the silicon substrate 100 corresponds to the light-receiving surface of the solar cell, and the back surface of the silicon substrate 100 corresponds to the back surface of the solar cell.

[0059] Optionally, the silicon substrate 100 can be a single crystal silicon wafer, which is a single crystal obtained by slowly cooling the molten silicon raw material. The crystal structure is tightly ordered, and the single crystal silicon wafer has high conversion efficiency, stability and service life.

[0060] Optionally, the silicon substrate 100 can be a polycrystalline silicon wafer, which is a form of elemental silicon. When the molten elemental silicon solidifies under supercooling conditions, the silicon atoms arrange in a diamond lattice form to form many crystal nuclei. If these crystal nuclei grow into grains with different crystal plane orientations, these grains combine to form polycrystalline silicon.

[0061] Optionally, the surface of the silicon substrate 100 can adopt a polished surface or a textured surface, which is not limited. The textured surface is obtained by a texturing process on the surface of the silicon substrate 100 to form a pyramid structure with uneven surface. The light-trapping effect of the textured surface is used to increase the absorption of sunlight, reduce the reflectivity, improve the short-circuit current, and improve the photoelectric conversion efficiency of the solar cell.

[0062] Optionally, the texturing process includes, but is not limited to, acid texturing, alkali texturing, mechanical texturing, electrochemical texturing, reactive ion etching texturing, laser texturing, mask texturing, and the like, which are not described herein.

[0063] The p-type doped region 110 is a positive electrode region of the solar cell, and the n-type doped region 120 is a negative electrode region of the solar cell. For example, a positive electrode region can be formed by doping a trivalent element such as boron on an n-type silicon wafer, and a negative electrode region can be formed by doping a pentavalent element such as phosphorus on the n-type silicon wafer, which are not described herein.

[0064] Optionally, the p-type doped region 110 and the n-type doped region 120 each include any one of polycrystalline silicon, amorphous silicon, microcrystalline silicon, and single crystal silicon.

[0065] The p-type doped region 110 and the n-type doped region 120 are alternately distributed along a first direction on the back surface of the silicon substrate 100, that is, there is an n-type doped region 120 between two p-type doped regions 110, and there is a p-type doped region 110 between two n-type doped regions 120. For ease of understanding, the extension direction of the line segment L1 is taken as the first direction, as shown in FIG. 1.

[0066] The p-type fine grid 310 and the n-type fine grid 320 are metal fine grids of the solar cell, wherein the p-type fine grid 310 is a positive electrode metal fine grid for collecting current of the p-type doped region, and the n-type fine grid 320 is a negative electrode metal fine grid for collecting current of the n-type doped region.

[0067] As a possible implementation, the solar cell further has a main grid (not shown in the figure) including a positive electrode main grid and a negative electrode main grid, wherein the positive electrode main grid is connected with the plurality of positive electrode fine grids for collecting current collected by the plurality of positive electrode fine grids, and the negative electrode main grid is connected with the plurality of negative electrode fine grids for collecting current collected by the plurality of negative electrode fine grids.

[0068] Optionally, the main grid and the fine grid are cross arranged, preferably, the main grid and the fine grid are perpendicular, for example, the main grid extends longitudinally and the fine grid extends transversely, which are not described herein.

[0069] Since the p-type doped region 110 and the n-type doped region 120 have opposite polarities, an electrical isolation is needed between the p-type doped region 110 and the n-type doped region 120. For example, the electrical isolation between the p-type doped region 110 and the n-type doped region 120 is achieved by arranging an isolation region 130 between the p-type doped region 110 and the n-type doped region 120.

[0070] In implementation, the extension direction of the isolation region 130 is perpendicular or substantially perpendicular to the first direction, for example, when the first direction is transverse, the extension direction of the isolation region 130 is longitudinal, and when the first direction is longitudinal, the extension direction of the isolation region 130 is transverse.

[0071] The isolation region 130 is provided with a velvet structure made by using the velvet making process described above. By using the light trapping effect of the velvet structure in the isolation region 130, the light reflection efficiency of the back surface of the solar cell is improved, and the photoelectric conversion efficiency of the solar cell is further improved.

[0072] In the first direction, the ratio of the width of the isolation region 130 to the width of the n-type doped region 120 is C1, For example, C1 is any one of 1 / 2, 3 / 4, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 1, 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.9, or up to 3, without limitation.

[0073] Optionally, the width of the isolation region 130 is 200-300 microns, for example, the width of the isolation region 130 is 210 microns, 220 microns, 221 microns, 225 microns, 228 microns, 230 microns, 240 microns, 250 microns, 260 microns, 270 microns, 280 microns, 290 microns, 291 microns, 292 microns, or any one of 200-300 microns, without limitation.

[0074] By increasing the width of the isolation region 130, the area of the velvet structure in the isolation region 130 is further increased, the light reflection efficiency is improved, on the other hand, when the width of the isolation region 130 is increased, the width of the p-type doped region 110 and the n-type doped region 120 will be correspondingly reduced, causing the loss of photoelectric conversion efficiency of the solar cell, by designing the ratio of the width of the isolation region 130 to the width of the n-type doped region 120 to be in the above range, the improvement of the photoelectric conversion efficiency of the solar cell is greater than the loss of efficiency, and the photoelectric conversion efficiency of the solar cell is improved.

[0075] In some possible embodiments, the ratio C1 of the width of the isolation region 130 to the width of the n-type doped region 120 is For example, C1 is any one of 1 / 2, 3 / 4, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or up to 2, without limitation.

[0076] By the above arrangement, the photoelectric conversion efficiency of the solar cell can be further improved.

[0077] In some optional embodiments, the width of the n-type doped region 120 is greater than or equal to the width of the p-type doped region 110.

[0078] As a possible implementation, referring to FIG. 1, the n-doped region 120 and the p-doped region 110 are rectangular structures. Due to the high conductivity of the n-doped region 120 compared to the p-doped region 110, the n-doped region 120 has a stronger lateral transmission capability than the p-doped region 110, and can transmit a greater distance. Therefore, by setting the width of the n-doped region 120 to be greater than or equal to the width of the p-doped region 110, and according to the corresponding lateral transmission capabilities of the two, the matching of the carrier transmission distance is achieved, the current collection is balanced, a smaller series resistance and a higher fill factor are obtained, and the conversion efficiency is further improved.

[0079] As a possible implementation, due to the passivation characteristics of the highly doped n-doped region 120 being better than those of the p-doped region 110, the width of the p-doped region 110 can be reduced and the width of the n-doped region 120 can be increased, so that the proportion of the passivation contact area of the n-type polysilicon material layer is higher, the overall passivation level of the battery is higher, the recombination loss is lower, and the conversion efficiency is further improved.

[0080] In some optional embodiments, the ratio of the width of the n-doped region 120 to the width of the p-doped region 110 is D1, and 1≤D1≤9. For example, D1 is 1.1, 1.5, 1.8, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, or any value within the range of 1 to 9, but is not limited thereto.

[0081] In practice, if the ratio between the width of the n-doped region 120 and the width of the p-doped region 110 is too low, the improvement effect of the series resistance and the fill factor is not good, and if the ratio between the width of the n-doped region 120 and the width of the p-doped region 110 is too high, the width of the p-doped region 110 is too narrow and the short-circuit current is too low, which affects the conversion efficiency.

[0082] Alternatively, the ratio D1 of the width of the n-doped region 120 to the width of the p-doped region 110 is 1.5≤D1≤4. For example, D1 is 1.6, 1.7, 1.8, 2, 2.1, 2.2, 2.3, 2.5, 2.6, 2.8, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, or any value within the range of 1.5 to 4, without specific limitation. Through the above setting, a smaller series resistance and a higher fill factor can be obtained.

[0083] In some embodiments, the width of the p-type doped region 110 is between 100 microns and 900 microns. For example, the width of the p-type doped region 110 is 110 microns, 120 microns, 130 microns, 140 microns, 150 microns, 180 microns, 200 microns, 210 microns, 250 microns, 300 microns, 350 microns, 400 microns, 450 microns, 500 microns, 550 microns, 600 microns, 650 microns, 700 microns, 750 microns, 800 microns, 850 microns, or any value between 100 microns and 900 microns, without limitation.

[0084] In some embodiments, the width of the p-type doped region 110 is between 100 microns and 900 microns. For example, the width of the p-type doped region 110 is 110 microns, 120 microns, 130 microns, 140 microns, 150 microns, 180 microns, 200 microns, 210 microns, 250 microns, 300 microns, 350 microns, 400 microns, 450 microns, 500 microns, 550 microns, 600 microns, 650 microns, 700 microns, 750 microns, 800 microns, 850 microns, or any value between 100 microns and 900 microns, without limitation.

[0085] In some embodiments, the width of the p-type doped region 110 is between 100 microns and 900 microns. For example, the width of the p-type doped region 110 is 110 microns, 120 microns, 130 microns, 140 microns, 150 microns, 180 microns, 200 microns, 210 microns, 250 microns, 300 microns, 350 microns, 400 microns, 450 microns, 500 microns, 550 microns, 600 microns, 650 microns, 700 microns, 750 microns, 800 microns, 850 microns, or any value between 100 microns and 900 microns, without limitation.

[0086] In some embodiments, the width of the p-type doped region 110 is between 100 microns and 900 microns. For example, the width of the p-type doped region 110 is 110 microns, 120 microns, 130 microns, 140 microns, 150 microns, 180 microns, 200 microns, 210 microns, 250 microns, 300 microns, 350 microns, 400 microns, 450 microns, 500 microns, 550 microns, 600 microns, 650 microns, 700 microns, 750 microns, 800 microns, 850 microns, or any value between 100 microns and 900 microns, without limitation.

[0087] In some embodiments, the width of the p-type doped region 110 is between 100 microns and 900 microns. For example, the width of the p-type doped region 110 is 110 microns, 120 microns, 130 microns, 140 microns, 150 microns, 180 microns, 200 microns, 210 microns, 250 microns, 300 microns, 350 microns, 400 microns, 450 microns, 500 microns, 550 microns, 600 microns, 650 microns, 700 microns, 750 microns, 800 microns, 850 microns, or any value between 100 microns and 900 microns, without limitation.

[0088] In some embodiments, the sum of the widths of the single p-type doped region 110, the single n-type doped region 120, and the single isolation region 130 is 450 microns to 4.8 millimeters, for example, the sum of the widths of the single p-type doped region 110, the single n-type doped region 120, and the single isolation region 130 is any value in the range of 450 microns, 460 microns, 470 microns, 480 microns, 490 microns, 500 microns, 600 microns, 700 microns, 1100 microns, 1300 microns, 2200 microns, 3600 microns, 4100 microns, 4200 microns, 4300 microns, 4400 microns, 4500 microns, 4600 microns, 4700 microns, or 450 microns to 4.8 millimeters, without specific limitation.

[0089] Through the above arrangement, the battery conversion efficiency is high, and the preparation difficulty is relatively low, ensuring a high production yield and better comprehensive performance.

[0090] In some embodiments, the sheet resistance of the p-type doped region 110 is greater than the sheet resistance of the n-type doped region 120.

[0091] In some embodiments, the sheet resistance of the p-type doped region 110 is 1.5 times to 10 times the sheet resistance of the n-type doped region 120, for example, the sheet resistance of the p-type doped region 110 can be designed to be 1.6 times, 1.7 times, 1.8 times, 1.9 times, 2 times, 2.2 times, 2.5 times, 3 times, 3.5 times, 4 times, 4.4 times, 5.1 times, 6.3 times, 7.8 times, 8.6 times, 9.1 times, or any value in the range of 1.5 times to 10 times the sheet resistance of the n-type doped region 120, without specific limitation.

[0092] Through the above arrangement, the sheet resistance of the n-type doped region 120 is low, and the lateral transport capacity is stronger than that of the p-type doped region 110. Moreover, the width of the n-type doped region 120 is greater than the width of the p-type doped region 110, which balances the current collection, improves the series resistance and the fill factor, and further improves the conversion efficiency.

[0093] In some optional embodiments, as shown in FIG. 1, the back contact solar cell provided by the application further comprises a passivation layer 200, which is arranged on the side of the n-doped region 120 and the p-doped region 110 away from the silicon substrate 100, and the passivation layer 200 is provided with a first window and a second window, the p-type fine grid 310 at least partially extends into the first window and contacts the p-doped region 110, and the n-type fine grid 320 at least partially extends into the second window and contacts the n-doped region 120. Part of the passivation layer 200 can also be arranged on the side of the isolation region 130 away from the silicon substrate 100, and in some embodiments, the thickness of the passivation layer 200 arranged on the isolation region 130 can be set to be thinner than the thickness of the passivation layer 200 arranged on the side of the n-doped region 120 and the p-doped region 110 away from the silicon substrate 100, so that the isolation region 130 is different from the n-doped region 120 and the p-doped region 110, and the n-doped region 120 and the p-doped region 110 facilitate the identification of the isolation region 130 and the printing of the grid lines.

[0094] The passivation layer 200 can effectively reduce the recombination of minority carriers and surface states on the back of the cell, which is conducive to improving the photoelectric conversion efficiency of the cell. On the other hand, the passivation layer 200 can also improve the stability of the solar cell, reduce the surface damage and oxidation reaction of the solar cell, and prolong the service life of the solar cell.

[0095] In some possible embodiments, the passivation layer 200 includes silicon nitride, silicon oxynitride, titanium dioxide, aluminum oxide, and diiron trioxide, without limitation.

[0096] As a possible implementation, the p-type fine grid 310 and the n-type fine grid 320 are made by printing silver paste and high-temperature sintering, and the silver paste includes a glass body that can corrode the passivation layer 200 during high-temperature sintering. That is, the first window and the second window of the passivation layer 200 can have the glass body corrode the passivation layer 200, so that the prepared p-type fine grid 310 extends into the first window and contacts the p-doped region 110, and the prepared n-type fine grid 320 extends into the second window and contacts the n-doped region 120.

[0097] In some optional embodiments, since the p-doped region 110 and the n-doped region 120 are arranged in turn and alternately, the edge closest to the silicon substrate 100 can be the p-doped region 110 or the n-doped region 120.

[0098] In some alternative embodiments, the distance between the p-type doped region or n-type doped region adjacent to the edge of the silicon substrate 100 and the edge of the silicon substrate 100 is smaller than the distance between the p-type doped region and the n-type doped region in the middle region of the silicon substrate 100. The p-type doped region adjacent to the edge of the silicon substrate 100 can be understood as the p-type doped region closest to the edge of the silicon substrate 100 among the p-type doped regions, or the n-type doped region closest to the edge of the silicon substrate 100 among the n-type doped regions.

[0099] When the p-type doped region 110 closest to the edge of the silicon substrate 100 is the p-type doped region 110, the distance between the p-type doped region 110 and the edge of the silicon substrate 100 is denoted as E1, and the distance between the p-type doped region 110 and the n-type doped region 120 in the middle region of the silicon substrate 100 is denoted as E2, E1 is smaller than E2, as shown in FIG. 2.

[0100] Similarly, when the n-type doped region 120 closest to the edge of the silicon substrate 100 is the n-type doped region 120, the distance between the n-type doped region 120 and the edge of the silicon substrate 100 is smaller than the distance between the p-type doped region 110 and the n-type doped region 120 in the middle region of the silicon substrate 100.

[0101] As a possible implementation, the back contact solar cell provided by the present application further comprises a main grid p-type doped region (not shown in the figure), the main grid p-type doped region is connected with the p-type doped region 110 in cross, the n-type doped region 120 is electrically isolated from the main grid p-type doped region, and the distance between the n-type doped region 120 and the main grid p-type doped region is smaller than the width of the isolation region 130.

[0102] In some possible embodiments, the isolation region 130 comprises a first region 131, a second region 132 and a groove 133.

[0103] The first region 131 is adjacent to the p-type doped region 110, the second region 132 is adjacent to the n-type doped region 120, and the groove 133 is located between the first region 131 and the second region 132, as shown in FIG. 3.

[0104] Optionally, the bottom of the groove 133 is textured. In implementation, the bottom of the groove 133 can be textured by the above-mentioned texturing process, which is not described herein. By designing the bottom of the groove 133 as textured, the reflectivity of light in the groove 133 can be effectively improved, thereby improving the photoelectric conversion efficiency of the solar cell.

[0105] In some possible embodiments, the first region 131 has a polished surface, and optionally, the second region 132 also has a polished surface.

[0106] As a possible implementation, the first region 131 is doped with p-type dopants, and the second region 132 is doped with n-type dopants, wherein the p-type dopants are trivalent elements such as boron or gallium, and the n-type dopants are pentavalent elements such as phosphorus or arsenic. Through the above arrangement, the power and power generation of the solar cell can be improved.

[0107] Embodiment Two

[0108] In some optional embodiments, the present application provides a photovoltaic module comprising the back contact solar cell as described above.

[0109] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the structure and implementation principle of the photovoltaic module described above can refer to the corresponding structure and implementation principle in the foregoing embodiment one, which will not be repeated here.

[0110] The back contact solar cell provided by the present application comprises a silicon substrate 100, a back surface of the silicon substrate 100 is provided with a plurality of p-type doped regions 110 and a plurality of n-type doped regions 120 which are arranged alternately in a first direction, a p-type fine grid 310 electrically connected with the p-type doped region 110, an n-type fine grid 320 electrically connected with the n-type doped region 120, and an isolation region 130 arranged between adjacent p-type doped region 110 and n-type doped region 120, wherein, in the first direction, the ratio C1 of the width of the isolation region 130 to the width of the n-type doped region 120 is Through the above arrangement, the width of the isolation region 130 is increased, and thus the area of the textured structure in the isolation region 130 is increased, the light reflection efficiency is improved, and the photoelectric conversion efficiency of the solar cell is improved.

[0111] Embodiment Three

[0112] In some optional embodiments, the present application provides a photovoltaic system comprising the photovoltaic module as described above.

[0113] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the structure and implementation principle of the photovoltaic system described above can refer to the corresponding structure and implementation principle in the foregoing embodiments one and two, which will not be repeated here.

[0114] The back contact solar cell provided in the application comprises a silicon substrate 100, a back surface of the silicon substrate 100 is provided with a plurality of p-type doped regions 110 and a plurality of n-type doped regions 120 arranged alternately in sequence along a first direction, a p-type fine grid 310 electrically connected with the p-type doped regions 110, an n-type fine grid 320 electrically connected with the n-type doped regions 120, and an isolation region 130 arranged between adjacent p-type doped regions 110 and n-type doped regions 120, in the first direction, a ratio C1 of the width of the isolation region 130 to the width of the n-type doped region 120 is Through the above arrangement, the width of the isolation region 130 is increased, and then the area of the textured structure in the isolation region 130 is increased, the light reflection efficiency is improved, and the photoelectric conversion efficiency of the solar cell is improved.

[0115] The above only is the preferred embodiment of the present disclosure, and does not limit the present disclosure, and any modification, equivalent replacement and improvement within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A back contact solar cell, comprising: a silicon substrate, a back surface of the silicon substrate being provided with a plurality of p-type doped regions and a plurality of n-type doped regions arranged alternately in a first direction; a p-type fine grid electrically connected to the p-type doped regions; an n-type fine grid electrically connected to the n-type doped regions; and an isolation region provided between adjacent p-type doped regions and n-type doped regions; the isolation region has a width of 200 micrometers to 300 micrometers. In the first direction, the ratio of the width of the isolation region to the width of the n-type doped region is C1, 2. The back contact solar cell of claim 1, wherein, The ratio C1 of the width of the isolation region to the width of the n-type doped region is 3. The back contact solar cell of claim 1 or 2, wherein, the n-type doped regions have a width greater than or equal to the width of the p-type doped regions.

4. The back contact solar cell of claim 1, wherein, a ratio of the width of the n-type doped regions to the width of the p-type doped regions is D1, and 1≤D1≤9.

5. The back contact solar cell of claim 4, wherein, the ratio D1 of the width of the n-type doped regions to the width of the p-type doped regions is 1.5≤D1≤4.

6. The back contact solar cell of claim 5, wherein, the p-type doped regions have a width of 100 micrometers to 900 micrometers.

7. The back contact solar cell of claim 2, wherein, a sum of the width of a single p-type doped region, a single n-type doped region, and a single isolation region is 400 micrometers to 9.3 millimeters.

8. The back contact solar cell of claim 1, wherein, a sum of the width of a single p-type doped region, a single n-type doped region, and a single isolation region is 450 micrometers to 4.8 millimeters.

9. The back contact solar cell of claim 8, wherein, the p-type doped regions have a sheet resistance greater than the sheet resistance of the n-type doped regions.

10. The back contact solar cell of claim 1, wherein, the p-type doped regions have a sheet resistance of 1.5 times to 10 times the sheet resistance of the n-type doped regions.

11. The back contact solar cell of claim 10, wherein, the back contact solar cell further comprises a passivation layer provided on a side of the n-type doped regions and the p-type doped regions opposite to the silicon substrate, and the passivation layer is provided with a first window and a second window, the p-type fine grid at least partially extends into the first window to contact the p-type doped regions, and the n-type fine grid at least partially extends into the second window to contact the n-type doped regions.

12. The back contact solar cell of claim 1, wherein, a distance between the p-type doped regions or the n-type doped regions adjacent to an edge of the silicon substrate and the edge of the silicon substrate is less than a distance between the p-type doped regions and the n-type doped regions in a middle region of the silicon substrate.

13. The back contact solar cell of claim 1, wherein, a main grid p-type doped region is further included, the main grid p-type doped region is cross-connected to the p-type doped regions, the n-type doped regions are electrically isolated from the main grid p-type doped regions, and a distance of electrical isolation between the n-type doped regions and the main grid p-type doped regions is less than the width of the isolation region.

14. The back contact solar cell of claim 1, wherein, the isolation region comprises a first region, a second region, and a trench; 15. The back contact solar cell of claim 1, wherein, the first region is adjacent to the p-type doped regions, the second region is adjacent to the n-type doped regions, and the trench is located between the first region and the second region. a bottom of the trench is a textured surface.

16. The back contact solar cell of claim 15, wherein, the first region has a polished surface.

17. The back contact solar cell of claim 15 or 16, wherein, the second region has a polished surface.

18. The back contact solar cell of claim 15 or 16, wherein, the first region is doped with a p-type dopant.

19. The back contact solar cell of claim 17, wherein, the second region is doped with an n-type dopant.

20. The back contact solar cell of claim 18, wherein, the p-type doped regions and the n-type doped regions each comprise any one of polycrystalline silicon, amorphous silicon, microcrystalline silicon, and single crystal silicon.

21. The back contact solar cell of claim 1, wherein, 22.A photovoltaic module comprising the back contact solar cell according to any one of claims 1 to 21. 23.A photovoltaic system comprising the photovoltaic module according to claim 22. ​

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