Solar cell and cell module

Abstract

The present disclosure provides a solar cell and a cell module. A solar cell passivated contact structure comprises: a tunneling layer; a first doped layer arranged on the side of the tunneling layer facing away from a silicon substrate; and a second doped layer arranged on the side of the first doped layer facing away from the silicon substrate and having a same doping type as the first doped layer. In a unit area, the total area of grain boundary gaps of the second doped layer is greater than the total area of grain boundary gaps of the first doped layer.

Description

Solar cells and battery modules

[0001] Cross-reference to related applications

[0002] This disclosure claims priority to Chinese Patent Application No. 202411449195.8, filed on October 16, 2024, with the State Intellectual Property Office of China, entitled “A Solar Cell and Passivated Contact Structure Thereof, Battery Module and Photovoltaic System”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the field of solar cell technology, specifically to solar cells and cell modules. Background Technology

[0004] Solar cells utilize the photovoltaic effect of semiconductors to convert sunlight into electrical energy. Solar cells mainly include bifacial contact solar cells and back-contact solar cells. Back-contact solar cells, with both positive and negative electrodes located on the back of the cell, completely avoid the shading caused by metal grid lines on the front surface, thus eliminating optical losses and significantly improving cell conversion efficiency compared to bifacial contact solar cells.

[0005] In existing technologies, the passivation contact structure of solar cells typically includes a tunneling layer and a doped layer sequentially stacked on the surface of a silicon substrate. The metal electrode of the solar cell contacts the doped layer to achieve passivation. To improve the passivation effect, the passivation contact structure of the solar cell typically includes at least two doped layers. However, the identical perforation degree of each doped layer in the passivation contact structure leads to significant parasitic absorption of sunlight, affecting the efficiency of the solar cell. Summary of the Invention

[0006] This disclosure provides a passivation contact structure for solar cells, aiming to solve the problem that existing passivation contact structures for solar cells suffer from large parasitic absorption of sunlight, which affects the efficiency of solar cells.

[0007] This disclosure is implemented by providing a passivated contact structure for a solar cell, comprising:

[0008] A tunneling layer disposed on the surface of a silicon substrate;

[0009] A first doped layer is disposed on the side of the tunneling layer opposite to the silicon substrate;

[0010] The second doped layer is disposed on the side of the first doped layer away from the silicon substrate, and the second doped layer has the same doping type as the first doped layer.

[0011] Within a unit area, the total area of ​​the intergranular gaps in the second doped layer is greater than the total area of ​​the intergranular gaps in the first doped layer.

[0012] In some embodiments, the first doped layer and the second doped layer are integrally formed or separately formed.

[0013] In some embodiments, the ratio of the total intergranular area of ​​the second doped layer to the total intergranular area of ​​the first doped layer is 6 to 10.

[0014] In some embodiments, the ratio of the area occupied by the grains of the first doped layer to the area occupied by the gaps between the grains is greater than the ratio of the area occupied by the grains of the second doped layer to the area occupied by the gaps between the grains.

[0015] In some embodiments, the ratio of the total grain area of ​​the second doped layer to the total intergranular area is 2.3% to 32.3%.

[0016] In some embodiments, the deposition temperature of the first doped layer is lower than that of the second doped layer, and the flow rate of the reactant gas introduced during the deposition of the first doped layer is the same as that introduced during the deposition of the second doped layer.

[0017] In some embodiments, the deposition temperature of the second doped layer is 586–605°C, and the deposition temperature of the first doped layer is 550–585°C.

[0018] In some embodiments, the deposition temperature of the first doped layer is greater than the deposition temperature of the second doped layer, and the flow rate of the reactant gas introduced during the deposition of the second doped layer is greater than the flow rate of the reactant gas introduced during the deposition of the first doped layer.

[0019] In some embodiments, the deposition temperature of the second doped layer is 585–605°C; and the deposition temperature of the first doped layer is 606–680°C.

[0020] In some embodiments, the solar cell passivation contact structure further includes:

[0021] A passivation layer is disposed between the first doped layer and the second doped layer.

[0022] In some embodiments, the average grain size of the first doped layer is smaller than the average grain size of the second doped layer.

[0023] In some embodiments, at least one of the first doped layer and the second doped layer is one or a combination of at least two of doped polycrystalline silicon, doped microcrystalline silicon, doped nanocrystalline silicon, and doped amorphous silicon.

[0024] This disclosure also provides a solar cell, including a silicon substrate, the silicon substrate including a light-facing surface and a back-lighting surface disposed opposite to the light-facing surface, at least one of the light-facing surface and the back-lighting surface being provided with the above-described solar cell passivation contact structure.

[0025] In some embodiments, the solar cell is a back-contact solar cell, the back surface is provided with a P-region and an N-region, and both the P-region and the N-region are provided with the solar cell passivation contact structure; the second doped layer of the P-region is a P-type doped layer, and the second doped layer of the N-region is an N-type doped layer.

[0026] In some embodiments, the solar cell is a double-sided contact solar cell, wherein one of the light-facing surface and the back-facing surface is provided with a P-region and the other is provided with an N-region, and both the P-region and the N-region are provided with the solar cell passivation contact structure; the second doped layer of the P-region is a P-type doped layer, and the second doped layer of the N-region is an N-type doped layer.

[0027] This disclosure also provides a battery assembly including the solar cell described above.

[0028] This disclosure also provides a photovoltaic system including the aforementioned battery module.

[0029] The passivation contact structure for a solar cell disclosed herein enhances the passivation effect of the solar cell by setting a first doped layer and a second doped layer on the side of the first doped layer facing away from the silicon substrate. Moreover, the total intergranular area of ​​the second doped layer per unit area is greater than that of the first doped layer, making the perforation degree of the second doped layer on the outer layer greater than that of the first doped layer on the inner layer. This reduces parasitic absorption of sunlight, improves the utilization efficiency of sunlight by the solar cell, and thus improves the cell efficiency. Attached Figure Description

[0030] Figure 1 is a schematic diagram of a passivated contact structure for a solar cell provided in Embodiment 1 of this disclosure;

[0031] Figure 2 is a SEM image of the second doped layer of a passivated contact structure for a solar cell provided in Embodiment 1 of this disclosure;

[0032] Figure 3 is a SEM image of the first doped layer of a passivated contact structure for a solar cell provided in Embodiment 1 of this disclosure;

[0033] Figure 4 is a schematic diagram of the structure of a solar cell provided in Embodiment 2 of this disclosure;

[0034] Figure 5 is a schematic diagram of the structure of a solar cell provided in Embodiment 3 of this disclosure.

[0035] The above figures include the following reference numerals:

[0036] 1. Passivation contact structure of solar cell; 11. Tunneling layer; 12. First doped layer; 13. Second doped layer; 14. Passivation layer; 15. Back passivation film layer; 2. Solar cell; 21. Silicon substrate; 211. Light-facing surface; 212. Back-facing surface; 213. P-region; 214. N-region; 215. Isolation region; 25. First electrode; 26. Second electrode. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this disclosure.

[0038] The passivation contact structure for a solar cell disclosed herein comprises a first doped layer and a second doped layer disposed on the side of the first doped layer away from the silicon substrate. Within a unit area, the total intergranular area of ​​the second doped layer is greater than that of the first doped layer. This results in the second doped layer on the outer layer having a greater degree of perforation than the first doped layer on the inner layer. By utilizing the first and second doped layers, the passivation effect of the solar cell is improved, while parasitic absorption of sunlight is reduced, thereby improving the utilization efficiency of sunlight by the solar cell and thus improving the cell efficiency.

[0039] Example 1

[0040] Referring to Figure 1, this disclosure provides a passivation contact structure 1 for a solar cell, comprising:

[0041] A tunneling layer 11 is disposed on the surface of the silicon substrate 21;

[0042] The first doped layer 12 is disposed on the side of the tunneling layer 11 away from the silicon substrate 21;

[0043] The second doped layer 13 is disposed on the side of the first doped layer 12 away from the silicon substrate 21, and the doping type of the second doped layer 13 is the same as that of the first doped layer 12.

[0044] Within a unit area, the total intergranular area of ​​the second doped layer 13 is greater than the total intergranular area of ​​the first doped layer 12.

[0045] In this embodiment, the total intergranular area of ​​the second doped layer 13 per unit area is greater than that of the first doped layer 12. This can be understood as follows: under the same area, the sum of the intergranular areas of all grains in the second doped layer 13 is greater than the sum of the intergranular areas of all grains in the first doped layer 12. The unit area can be the entire area of ​​the second doped layer 13 and the first doped layer 12, or a portion of the area of ​​the second doped layer 13 and the first doped layer 12. For the first doped layer 12 and the second doped layer 13, a larger intergranular area indicates a more porous doped layer structure and a greater degree of perforation; conversely, a smaller intergranular area indicates a denser doped layer structure and a smaller degree of perforation. As shown in Figures 2-3, the total intergranular area of ​​both the second doped layer 13 and the first doped layer 12 can be obtained by SEM measurement. Figure 2 shows that the total intergranular area of ​​the second doped layer 13 is greater than that of the first doped layer 12 shown in Figure 3.

[0046] The passivation contact structure for a solar cell disclosed herein, by providing a first doped layer 12 and a second doped layer 13 disposed on the side of the first doped layer 12 facing away from the silicon substrate 21, can enhance the passivation effect of the solar cell by utilizing the first doped layer 12 and the second doped layer 13. Moreover, per unit area, the total intergranular area of ​​the second doped layer 13 is greater than that of the first doped layer 12, making the perforation degree of the second doped layer 13 located on the outer layer greater than that of the first doped layer 12 located on the inner layer. While utilizing the first doped layer 12 and the second doped layer 13 to enhance the passivation effect, by increasing the total intergranular area of ​​the second doped layer 13, i.e., increasing the perforation degree of the second doped layer 13, the parasitic absorption of sunlight by the doped layer can be reduced, thereby improving the utilization efficiency of sunlight by the solar cell and thus improving the cell efficiency.

[0047] In this embodiment, the silicon substrate 21 can be a P-type silicon substrate or an N-type silicon substrate. The surface of the silicon substrate 21 can be the light-facing side or the back-facing side of the solar cell. The passivation contact structure of the solar cell can be disposed in the P-region or the N-region of the solar cell.

[0048] As one embodiment of this disclosure, the tunneling layer 11 is one or a combination of at least two of silicon oxide, silicon oxynitride, and silicon nitride.

[0049] In this embodiment, the material of the tunneling layer 11 can be one or a combination of at least two of silicon oxide, silicon oxynitride, and silicon nitride. The tunneling layer 11 serves to tunnel through and passivate the surface of the silicon substrate 21, thereby improving the efficiency of the solar cell. The thickness of the tunneling layer 11 can be set according to actual conditions. For example, the thickness of the tunneling layer 11 can be 0.5–5 nanometers.

[0050] Specifically, when the passivation contact structure 1 of the solar cell is disposed in the P region of the solar cell, the first doped layer 12 and the second doped layer 13 are P-type doped layers, and the electrode of the P region of the solar cell is in contact with the second doped layer 13; when the passivation contact structure of the solar cell is disposed in the N region of the solar cell, the first doped layer 12 and the second doped layer 13 are N-type doped layers, and the electrode of the N region of the solar cell is in contact with the second doped layer 13.

[0051] As an embodiment of this disclosure, the first doped layer 12 and / or the second doped layer 13 are one or a combination of at least two of doped polycrystalline silicon, doped microcrystalline silicon, doped nanocrystalline silicon, and doped amorphous silicon.

[0052] The materials of the first doped layer 12 and the second doped layer 13 can be the same or different, depending on actual needs. The first doped layer 12 and the second doped layer 13 can be doped polycrystalline silicon, doped microcrystalline silicon, doped nanocrystalline silicon, or doped amorphous silicon. Alternatively, the first doped layer 12 and the second doped layer 13 can be a combination of at least two of these materials. In some embodiments, both the first doped layer 12 and the second doped layer 13 are doped polycrystalline silicon.

[0053] In this embodiment, the first doped layer 12 and the second doped layer 13 have the same doping type; the first doped layer 12 and the second doped layer 13 are either P-type doped layers doped with P-type dopant or N-type doped layers doped with N-type dopant. The P-type dopant is a Group IIIA element dopant, and the N-type dopant is a Group VA element dopant. For example, the P-type dopant can be a boron dopant, and the N-type dopant can be a phosphorus dopant.

[0054] In this embodiment, the passivation contact structure of the solar cell includes at least two doped layers, namely, a first doped layer 12 and a second doped layer 13. Of course, the passivation contact structure of the solar cell may also include three or more doped layers. For example, the passivation contact structure of the solar cell may also include a third doped layer (not shown), which is disposed on the side of the second doped layer 13 facing away from the silicon substrate 21. Within a unit area, the total intergranular area of ​​the third doped layer is greater than the total intergranular area of ​​the second doped layer 13, making the perforation degree of the outer third doped layer greater than that of the inner second doped layer 13. This can further improve the passivation effect of the cell and reduce parasitic absorption of sunlight, thereby improving the utilization efficiency of sunlight by the solar cell and ultimately improving the cell efficiency.

[0055] As one embodiment of this disclosure, the first doped layer 12 and the second doped layer 13 are integrally formed or separately formed.

[0056] In this embodiment, the first doped layer 12 and the second doped layer 13 are integrally formed, or the first doped layer 12 and the second doped layer 13 are separately formed. It can be understood that the first doped layer 12 and the second doped layer 13 are single-layer structures formed in one process, or the first doped layer 12 and the second doped layer 13 can be stacked structures formed in steps.

[0057] As an embodiment of this disclosure, the ratio of the total intergranular area of ​​the second doped layer 13 to the total intergranular area of ​​the first doped layer 12 is 6 to 10.

[0058] In this embodiment, the ratio of the total intergranular area of ​​the second doped layer 13 to the total intergranular area of ​​the first doped layer 12 is 6 to 10, so that the difference between the degree of perforation of the second doped layer 13 and the degree of perforation of the first doped layer 12 is within a suitable range. This can effectively improve the passivation effect of the battery and ensure small parasitic absorption of sunlight, thereby improving the utilization efficiency of the solar cell and thus improving the battery efficiency.

[0059] For example, the ratio of the total intergranular area of ​​the second doped layer 13 to the total intergranular area of ​​the first doped layer 12 can be 6.0, 6.2, 6.5, 6.8, 7.0, 7.1, 7.6, 7.9, 8.0, 8.3, 8.7, 9.0, 9.4, 9.8, or 10.0.

[0060] As an embodiment of this disclosure, the total area of ​​the intergranular space of the first doped layer 12 accounts for 0.5% to 3%, and the total area of ​​the intergranular space of the second doped layer 13 accounts for 3% to 30%.

[0061] In this embodiment, the total area ratio of the intergranular gaps in the first doped layer 12 is the ratio of the total area of ​​the intergranular gaps in the first doped layer 12 to the total area of ​​the first doped layer 12, and the total area ratio of the intergranular gaps in the second doped layer 13 is the ratio of the total area of ​​the intergranular gaps in the second doped layer 13 to the total area of ​​the second doped layer 13.

[0062] This can be understood as follows: under the same area, the total area ratio of the intergranular gaps in the first doped layer 12 is 0.5% to 3%, and the total area ratio of the intergranular gaps in the second doped layer 13 is 3% to 30%. Setting the total area ratio of the intergranular gaps in the second doped layer 13 and the first doped layer 12 within a suitable range can effectively improve the passivation effect of the cell, improve the utilization efficiency of solar cells to sunlight, thereby improving the cell efficiency, and facilitate the processing and preparation of the first doped layer 12 and the second doped layer 13.

[0063] As an embodiment of this disclosure, the ratio of the total grain area of ​​the first doped layer 12 to the total intergranular area per unit area is greater than the ratio of the total grain area of ​​the second doped layer 13 to the total intergranular area.

[0064] In this embodiment, the ratio of the total area of ​​the grains in the first doped layer 12 to the total area of ​​the intergranular spaces can be understood as the ratio of the total area of ​​all grains in the first doped layer 12 per unit area to the total area of ​​all intergranular spaces; the ratio of the total area of ​​the grains in the second doped layer 13 to the total area of ​​the intergranular spaces can be understood as the ratio of the total area of ​​all grains in the second doped layer 13 per unit area to the total area of ​​all intergranular spaces. Since the ratio of the total area of ​​the grains in the first doped layer 12 to the total area of ​​the intergranular spaces per unit area is greater than that of the second doped layer 13, the proportion of intergranular spaces in the first doped layer 12 is less than the proportion of the total intergranular space in the second doped layer 13. This results in a greater degree of perforation in the second doped layer 13 than in the first doped layer 12, which is beneficial for improving the passivation effect of the battery and achieving less parasitic absorption of sunlight.

[0065] As one embodiment of this disclosure, the ratio of the total grain area of ​​the second doped layer 13 to the total intergranular area is 2.3% to 32.3%.

[0066] In this embodiment, the ratio of the total area of ​​the grains of the second doped layer 13 to the total area of ​​the intergranular spaces is within 2.3% to 32.3%, which makes the degree of hollowing out of the second doped layer 13 located on the outer layer more suitable. This can improve the passivation effect of the battery and reduce the parasitic absorption of sunlight, thereby improving the utilization efficiency of the solar cell and thus improving the battery efficiency.

[0067] In this embodiment, since the grain arrangement of the doped layer is related to the deposition temperature and the flow rate of the deposition reaction gas, the intergranular area can be controlled by adjusting the deposition temperature and the flow rate of the deposition reaction gas. The specific type of reaction gas is not limited and can be determined according to the specific material of the doped layer. For example, if the doped layer is polycrystalline silicon, the reaction gas can be silane and nitrogen.

[0068] As an embodiment of this disclosure, the deposition temperature of the first doped layer 12 is lower than the deposition temperature of the second doped layer 13, and the flow rate of the reactant gas introduced during the deposition of the first doped layer 12 is the same as the flow rate of the reactant gas introduced during the deposition of the second doped layer 13.

[0069] In this embodiment, when the flow rate of the reactive gas introduced during the deposition of the first doped layer 12 is the same as the flow rate of the reactive gas introduced during the deposition of the second doped layer 13, the deposition temperature of the first doped layer 12 is set to be lower than the deposition temperature of the second doped layer 13. This makes the total intergranular area of ​​the second doped layer 13 larger than the total intergranular area of ​​the first doped layer 12, thereby making the perforation degree of the second doped layer 13 greater than that of the first doped layer 12, and making the structure of the second doped layer 13 more porous than that of the first doped layer 12.

[0070] As an embodiment of this disclosure, the deposition temperature of the second doped layer 13 is 586-605°C, and the deposition temperature of the first doped layer 12 is 550-585°C.

[0071] In this embodiment, when the flow rate of the reactive gas introduced during the deposition of the first doped layer 12 is the same as the flow rate of the reactive gas introduced during the deposition of the second doped layer 13, the deposition temperature of the second doped layer 13 is 586–605°C, and the deposition temperature of the first doped layer 12 is 550–585°C. The deposition temperature of the second doped layer 13 can be any value within the range of 586–605°C, and the deposition temperature of the first doped layer 12 can be any value within the range of 550–585°C, as long as the deposition temperature of the first doped layer 12 is lower than the deposition temperature of the second doped layer 13.

[0072] In another embodiment of this disclosure, the deposition temperature of the first doped layer 12 is greater than the deposition temperature of the second doped layer 13, and the flow rate of the reactant gas introduced during the deposition of the second doped layer 13 is greater than the flow rate of the reactant gas introduced during the deposition of the first doped layer 12.

[0073] In this embodiment, the flow rate of the reactive gas introduced during the deposition of the second doped layer 13 is greater than the flow rate of the reactive gas introduced during the deposition of the first doped layer 12, and the deposition temperature of the first doped layer 12 is greater than the deposition temperature of the second doped layer 13. This also makes the total intergranular area of ​​the second doped layer 13 greater than the total intergranular area of ​​the first doped layer 12, thereby making the perforation degree of the second doped layer 13 greater than that of the first doped layer 12, and making the structure of the second doped layer 13 more porous than that of the first doped layer 12.

[0074] As an embodiment of this disclosure, the deposition temperature of the second doped layer 13 is 585–605°C; the deposition temperature of the first doped layer 12 is 606–680°C.

[0075] In this embodiment, when the flow rate of the reactive gas introduced during the deposition of the second doped layer 13 is greater than the flow rate of the reactive gas introduced during the deposition of the first doped layer 12, the deposition temperature of the second doped layer 13 is 585–605°C; and the deposition temperature of the first doped layer 12 is 606–680°C. The deposition temperature of the second doped layer 13 can be any value within the range of 585–605°C, and the deposition temperature of the first doped layer 12 can be any value within the range of 606–680°C, as long as the deposition temperature of the first doped layer 12 is lower than the deposition temperature of the second doped layer 13.

[0076] As one embodiment of this disclosure, the average grain size of the first doped layer 12 is smaller than the average grain size of the second doped layer 13.

[0077] In this embodiment, the average grain size of the first doped layer 12 and the average grain size of the second doped layer 13 can be measured using XRD, SEM, and TEM methods. The average grain size of the first doped layer 12 is smaller than that of the second doped layer 13. This can be understood as the average value of all grain sizes in the first doped layer 12 per unit area being greater than the average value of all grain sizes in the second doped layer 13 per unit area. In other words, within a unit area, the grain size in the first doped layer 12 is smaller and the number of grains is greater. Compared to the second doped layer 13, this increases the density of the first doped layer 12, making its structure more compact and resulting in better passivation.

[0078] As one embodiment of this disclosure, it also includes:

[0079] The passivation layer 14 is disposed between the first doped layer 12 and the second doped layer 13.

[0080] In this embodiment, a passivation layer 14 is provided between the first doped layer 12 and the second doped layer 13. The passivation effect can be further enhanced by the passivation layer 14, and the passivation layer 14 can block the ablation of the metal paste. Therefore, the design thickness of the second doped layer 13 can be reduced, and the cost can be reduced.

[0081] The passivation layer 14 can be one or a combination of silicon oxide, silicon nitride, and silicon carbide. Of course, the passivation layer 14 may not be required between the first doped layer 12 and the second doped layer 13, and the first doped layer 12 and the second doped layer 13 may be in direct contact.

[0082] As one embodiment of this disclosure, the solar cell passivation contact structure 1 further includes:

[0083] The back passivation film 15 is disposed on the side of the second doped layer 13 away from the silicon substrate 21.

[0084] In this embodiment, the electrode of the solar cell contacts the second doped layer 13 through the back passivation film layer 15. The back passivation film layer 15 serves to passivate and protect the back side of the second doped layer 13, thereby improving cell efficiency. The back passivation film layer 15 can be one or a combination of at least two of silicon nitride, silicon oxynitride, and silicon oxide. For example, the back passivation film layer 15 can be aluminum oxide and silicon nitride sequentially stacked on the second doped layer 13, achieving both good passivation of the back side of the second doped layer and good protection for it.

[0085] Example 2

[0086] Please refer to Figure 4. This embodiment provides a solar cell 2, which includes a silicon substrate 21. The silicon substrate 21 includes a light-facing surface 211 and a backlight surface 212 disposed opposite to the light-facing surface 211. The backlight surface 212 is provided with the solar cell passivation contact structure 1 of the above embodiment 1.

[0087] In this embodiment of the present disclosure, the solar cell is a back-contact solar cell. The back surface 212 of the back-contact solar cell is provided with a P-region 213 and an N-region 214. Both the P-region 213 and the N-region 214 are provided with a solar cell passivation contact structure 1. The second doped layer 13 of the P-region 213 is a P-type doped layer, and the second doped layer 13 of the N-region 214 is an N-type doped layer.

[0088] As one embodiment of this disclosure, the solar cell 2 further includes:

[0089] A first electrode 25 is provided in the P region 213, and the first electrode 25 is in contact with the second doped layer 13 of the P region 213;

[0090] A second electrode 26 is provided in the N region 214, and the second electrode 26 is in contact with the second doped layer 13 of the N region 214.

[0091] In this embodiment, the first electrode 25 contacts the second doped layer 13 of the P-region 213 to form an ohmic contact, and the second electrode 26 contacts the second doped layer 13 of the N-region 214 to achieve current extraction from the solar cell. Specifically, the first electrode 25 passes through the back passivation film 15 at the P-region 213 to contact the second doped layer 13, and the second electrode 26 passes through the back passivation film 15 at the N-region 214 to contact the second doped layer 13.

[0092] In this embodiment, there are multiple P-regions 213 and multiple N-regions 214, which are arranged alternately and at intervals. An isolation region 215 is provided between adjacent P-regions 213 and N-regions 214. The isolation region 215 can be a trench or a gap, ensuring good isolation between the P-regions 213 and N-regions 214.

[0093] In Figure 4, both region P 213 and region N 214 of the back-contact solar cell are provided with the solar cell passivation contact structure of Embodiment 1 described above. Of course, in other embodiments, only one of region P 213 and region N 214 may be provided with the solar cell passivation contact structure of Embodiment 1 described above. For example, only region P 213 may be provided with the solar cell passivation contact structure of Embodiment 1 described above, while region N 214 may be provided with other conventional solar cell passivation contact structures; or, only region N 214 may be provided with the solar cell passivation contact structure of Embodiment 1 described above, while region P 213 may be provided with other conventional solar cell passivation contact structures.

[0094] This embodiment provides a passivation contact structure for a solar cell. Because the passivation contact structure includes a first doped layer 12 and a second doped layer 13, the total intergranular area of ​​the second doped layer 13 per unit area is greater than that of the first doped layer 12. This results in a greater degree of perforation in the outer second doped layer 13 compared to the inner first doped layer 12. By utilizing the first doped layer 12 and the second doped layer 13, the passivation effect of the cell can be improved, while parasitic absorption of sunlight can be reduced, thereby increasing the solar cell's utilization efficiency and ultimately improving the cell efficiency.

[0095] Example 3

[0096] Please refer to Figure 5. This embodiment provides a solar cell 2, which includes a silicon substrate 21. The silicon substrate 21 includes a light-facing surface 211 and a backlight surface 212 disposed opposite to the light-facing surface 211. Both the light-facing surface 211 and / or the backlight surface 212 are provided with the solar cell passivation contact structure of the above embodiment 1.

[0097] As one embodiment of this disclosure, the solar cell 2 is a double-sided contact solar cell. One of the light-facing surface 211 and the back-lighting surface 212 is provided with a P-region 213, and the other with an N-region 214. Both the P-region 213 and the N-region 214 are provided with solar cell passivation contact structures. The second doped layer 13 of the P-region 213 is a P-type doped layer, and the second doped layer 13 of the N-region 214 is an N-type doped layer. Figure 5 only illustrates the case where the P-region 213 is located on the light-facing surface 211 and the N-region 214 is located on the back-lighting surface 212. Of course, the P-region 213 can also be located on the back-lighting surface 212, and the N-region 214 can be located on the light-facing surface 211.

[0098] As one embodiment of this disclosure, the solar cell 2 further includes:

[0099] A first electrode 25 is provided in the P region 213, and the first electrode 25 is in contact with the second doped layer 13 of the P region 213;

[0100] A second electrode 26 is provided in the N region 214, and the second electrode 26 is in contact with the second doped layer 13 of the N region 214.

[0101] In this embodiment, the first electrode 25 contacts the second doped layer 13 of the P-region 213 to form an ohmic contact, and the second electrode 26 contacts the second doped layer 13 of the N-region 214 to achieve current extraction from the solar cell. Specifically, the first electrode 25 passes through the back passivation film 15 at the P-region 213 to contact the second doped layer 13, and the second electrode 26 passes through the back passivation film 15 at the N-region 214 to contact the second doped layer 13.

[0102] In this embodiment, there are multiple P-regions 213 and multiple N-regions 214. Multiple P-regions 213 are alternately and spaced on the light-facing surface 211, and multiple N-regions 214 are alternately and spaced on the backlight surface 212; or, multiple N-regions 214 are alternately and spaced on the light-facing surface 211, and multiple P-regions 213 are alternately and spaced on the backlight surface 212. Figure 5 only illustrates the case where multiple P-regions 213 are alternately and spaced on the light-facing surface 211, and multiple N-regions 214 are alternately and spaced on the backlight surface 212.

[0103] In Figure 5, both region P 213 and region N 214 of the back-contact solar cell are provided with the solar cell passivation contact structure of Embodiment 1 described above. Of course, in other embodiments, only one of region P 213 and region N 214 may be provided with the solar cell passivation contact structure of Embodiment 1 described above. For example, only region P 213 may be provided with the solar cell passivation contact structure of Embodiment 1 described above, while region N 214 may be provided with other conventional solar cell passivation contact structures; or, only region N 214 may be provided with the solar cell passivation contact structure of Embodiment 1 described above, while region P 213 may be provided with other conventional solar cell passivation contact structures.

[0104] In this embodiment, P-region 213 can completely cover the light-facing surface 211 of the silicon substrate 21, or it can only cover a portion of the light-facing surface 211 of the silicon substrate 21; N-region 214 can completely cover the back-facing surface 212 of the silicon substrate 21, or it can only cover a portion of the back-facing surface 212 of the silicon substrate 21. In some embodiments, P-region 213 covers a portion of the light-facing surface 211 of the silicon substrate 21, and adjacent P-regions 213 are spaced apart, so that the doped layer of the light-facing surface 211 only covers a portion of the light-facing surface 211 of the silicon substrate 21; N-region 214 covers a portion of the back-facing surface 212 of the silicon substrate 21, and adjacent N-regions 214 are spaced apart, so that the doped layer of the back-facing surface 212 only covers a portion of the light-facing surface 211 of the silicon substrate 21, which can reduce parasitic light absorption.

[0105] This embodiment provides a solar cell using the passivation contact structure. Since the passivation contact structure of the solar cell is provided with a first doped layer 12 and a second doped layer 13, the total area of ​​the intergranular gaps in the second doped layer 13 per unit area is greater than the total area of ​​the intergranular gaps in the first doped layer 12. This makes the hollowness of the outer second doped layer 13 greater than the hollowness of the inner first doped layer 12. By utilizing the first doped layer 12 and the second doped layer 13, the passivation effect of the cell is improved, and the parasitic absorption of sunlight can be reduced, thereby improving the utilization efficiency of the solar cell and thus improving the cell efficiency.

[0106] Example 4

[0107] This disclosure also provides a battery assembly, which includes the solar cell of Embodiment 2 or Embodiment 3 described above. It should be noted that this battery assembly has the same or similar beneficial effects as the solar cell 2 described above, and the related aspects between the two can be referred to each other; to avoid repetition, they will not be repeated here.

[0108] In this embodiment, multiple solar cells 2 in the battery module can be connected in series to form a battery string, thereby realizing the series current collection and output. For example, the battery cells can be connected in series by setting solder strips (busbars, interconnecting strips), conductive backplates, etc.

[0109] It is understood that in such embodiments, the battery assembly may also include a metal frame, a backsheet, photovoltaic glass, and an encapsulating film. The encapsulating film may be filled between the front and back of the solar cell 2, the photovoltaic glass, adjacent cells, etc. As a filler, it may be a transparent colloid with good light transmittance and aging resistance. For example, the encapsulating film may be an EVA film or a POE film, and the specific choice can be made according to the actual situation, without limitation.

[0110] Photovoltaic glass can be applied to the encapsulating film on the front side of solar cell 2. This photovoltaic glass can be ultra-clear glass, possessing high light transmittance, high transparency, and superior physical, mechanical, and optical properties. For example, ultra-clear glass can achieve a light transmittance of over 92%, protecting the solar cell while minimizing impact on its efficiency. Simultaneously, the encapsulating film bonds the photovoltaic glass and solar cell 2 together, providing sealing, insulation, and waterproofing / moisture protection for the solar cell 2.

[0111] The backsheet can be attached to the encapsulating film on the back of the solar cell 2. The backsheet protects and supports the solar cell 2, providing reliable insulation, water resistance, and aging resistance. Multiple backsheet options are available, typically including tempered glass, acrylic glass, aluminum alloy TPT composite encapsulating film, etc., and the specific choice depends on the specific circumstances and is not limited here. The backsheet, solar cell 2, 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 solar cell module, providing stable support and installation. For example, the solar cell module can be installed at the desired location using the metal frame.

[0112] Example 5

[0113] This disclosure also provides a photovoltaic system, which includes the battery module of Embodiment 4 described above. It should be noted that this photovoltaic system has the same or similar beneficial effects as the solar cell 2, and the related aspects between the two can be referred to each other; to avoid repetition, they will not be repeated here.

[0114] In this embodiment, the photovoltaic system can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants. It can also be applied to 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 is understood that the application scenarios of the photovoltaic system are not limited to these; that is, the photovoltaic system can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may be an array combination of multiple solar cell modules; for example, multiple solar cell modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the combiner box, which can collect the current generated by the photovoltaic array. The collected current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.

[0115] The above are merely preferred embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A solar cell passivated contact structure, wherein, include: A tunneling layer disposed on the surface of a silicon substrate; A first doped layer is disposed on the side of the tunneling layer opposite to the silicon substrate; The second doped layer is disposed on the side of the first doped layer away from the silicon substrate, and the second doped layer has the same doping type as the first doped layer. Within a unit area, the total area of ​​the intergranular gaps in the second doped layer is greater than the total area of ​​the intergranular gaps in the first doped layer.

2. The solar cell passivated contact structure of claim 1, wherein, The first doped layer and the second doped layer are either integrally formed or separately formed.

3. The solar cell passivated contact structure of claim 1, wherein, The ratio of the total intergranular area of ​​the second doped layer to the total intergranular area of ​​the first doped layer is 6 to 10.

4. The solar cell passivated contact structure of claim 1, wherein, Within a unit area, the ratio of the area occupied by the grains of the first doped layer to the area occupied by the gaps between the grains is greater than the ratio of the area occupied by the grains of the second doped layer to the area occupied by the gaps between the grains.

5. The passivated contact solar cell structure of claim 1, wherein, The ratio of the total grain area to the total intergranular area of ​​the second doped layer is 2.3% to 32.3%.

6. The passivated contact solar cell structure of claim 1, wherein, The deposition temperature of the first doped layer is lower than that of the second doped layer, and the flow rate of the reactant gas introduced during the deposition of the first doped layer is the same as that introduced during the deposition of the second doped layer.

7. The passivated contact structure for a solar cell of claim 6, wherein, The deposition temperature of the second doped layer is 586–605°C, and the deposition temperature of the first doped layer is 550–585°C.

8. The passivated contact solar cell structure of claim 1, wherein, The deposition temperature of the first doped layer is greater than that of the second doped layer, and the flow rate of the reactant gas introduced during the deposition of the second doped layer is greater than that during the deposition of the first doped layer.

9. The passivated contact structure for a solar cell of claim 8, wherein, The deposition temperature of the second doped layer is 585–605°C; the deposition temperature of the first doped layer is 606–680°C.

10. The passivated contact structure for a solar cell of claim 1, wherein, The passivated contact structure for the solar cell also includes: A passivation layer is disposed between the first doped layer and the second doped layer.

11. The passivated contact solar cell structure of claim 1, wherein, The average grain size of the first doped layer is smaller than the average grain size of the second doped layer.

12. The passivated contact solar cell structure of claim 1, wherein, At least one of the first doped layer and the second doped layer is one or a combination of at least two of doped polycrystalline silicon, doped microcrystalline silicon, doped nanocrystalline silicon, and doped amorphous silicon.

13. A solar cell, wherein, The device includes a silicon substrate, the silicon substrate comprising a light-facing surface and a back-lighting surface disposed opposite to the light-facing surface, wherein at least one of the light-facing surface and the back-lighting surface is provided with a solar cell passivation contact structure as described in any one of claims 1 to 12.

14. The solar cell of claim 13, wherein, The solar cell is a back-contact solar cell, and the back surface is provided with a P-region and an N-region. Both the P-region and the N-region are provided with the passivation contact structure of the solar cell. The second doped layer of the P-region is a P-type doped layer, and the second doped layer of the N-region is an N-type doped layer.

15. The solar cell of claim 13, wherein, The solar cell is a double-sided contact solar cell, wherein one of the light-facing surface and the back-facing surface is provided with a P-region and the other is provided with an N-region, and both the P-region and the N-region are provided with the passivation contact structure of the solar cell; the second doped layer of the P-region is a P-type doped layer, and the second doped layer of the N-region is an N-type doped layer.

16. A battery assembly, wherein, Including the solar cell as described in any one of claims 13 to 15.

17. A photovoltaic system, wherein, Includes the battery assembly as described in claim 16.

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