Solar cell
By arranging the positive and negative electrode regions on the first surface of the solar cell substrate and covering the metallized region with a titanium oxide layer, the problem of insufficient passivation effect is solved, the electrical performance and conversion efficiency of the cell are improved, and the production cost is reduced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-18
- Publication Date
- 2026-03-24
AI Technical Summary
Existing solar cells have low passivation efficiency, which affects their electrical performance.
A positive electrode region and a negative electrode region are arranged on the first surface of the substrate, and a titanium oxide layer is covered on the metallized region of the positive electrode region to repair local defects in the substrate caused by laser film opening and improve the passivation effect.
This improved the short-circuit current, open-circuit voltage, fill factor, and photoelectric conversion efficiency of solar cells, while reducing production costs.
Smart Images
Figure CN224037753U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present disclosure relates to the field of batteries, in particular to a solar cell. BACKGROUND
[0002] With the rapid development of battery manufacturing technology, how to improve the electrical performance of solar cells has become one of the important research directions.
[0003] In the related art, the passivation effect of the solar cell is low, which in turn affects the electrical performance of the battery. UTILITY MODEL CONTENT
[0004] In order to overcome the problems in the related art, the present disclosure provides a solar cell.
[0005] According to the embodiments of the present disclosure, a solar cell is provided, comprising: a substrate and a positive electrode region and a negative electrode region on a first surface of the substrate; the positive electrode region comprises a first dielectric layer and a first doped layer covering the substrate, and the first doped layer covers the first dielectric layer; a first metallized region of the positive electrode region covers a titanium oxide layer in a corresponding region on the first doped layer, and a positive electrode is printed on the titanium oxide layer; a first non-metallized region of the positive electrode region covers a passivation layer in a corresponding region on the first doped layer, and a second surface of the substrate covers the passivation layer.
[0006] Optionally, the negative electrode region comprises a second dielectric layer and a second doped layer covering the substrate, and the second doped layer covers the second dielectric layer; a second metallized region and a second non-metallized region of the negative electrode region both cover a passivation layer in a corresponding region on the second doped layer, and a negative electrode is printed in a corresponding region on the passivation layer of the second metallized region.
[0007] Optionally, the thickness of the titanium oxide layer is 30-80 nm.
[0008] Optionally, the positive electrode is an aluminum electrode.
[0009] Optionally, the first dielectric layer is a silicon oxide layer.
[0010] Optionally, the first doped layer is a polycrystalline silicon layer doped with a P-type element.
[0011] Optionally, the first surface of the substrate further comprises an isolation region between the positive electrode region and the negative electrode region; and the passivation layer further covers the isolation region.
[0012] Optionally, the first surface of the substrate and the isolation region are textured structures.
[0013] Optionally, the passivation layer comprises an aluminum oxide layer and a silicon nitride layer, the silicon nitride layer being covered on the aluminum oxide layer.
[0014] Optionally, the thickness of the aluminum oxide layer is 2-15 nm, and the thickness of the silicon nitride layer is 60-90 nm.
[0015] By the above technical solution, the positive electrode region and the negative electrode region are arranged on the first surface of the substrate, so that the second surface of the substrate is not blocked by the grid lines, the short-circuit current of the battery is improved, and the conversion efficiency of the battery is improved. Covering the passivation layer on the positive electrode region can improve the open-circuit voltage, short-circuit current and conversion efficiency of the battery. On the basis of removing the passivation layer by laser opening film in the metallization region of the positive electrode region, covering the titanium oxide layer on the metallization region can repair the local defects of the substrate caused by laser opening film, and the passivation effect of the titanium oxide layer is improved relative to the original passivation layer. Covering the titanium oxide layer can further improve the minority carrier lifetime, open-circuit voltage and fill factor of the battery, thereby improving the photoelectric conversion efficiency and the electrical performance of the battery.
[0016] Other features and advantages of the present disclosure will be described in detail in the following detailed description section. BRIEF DESCRIPTION OF DRAWINGS
[0017] The accompanying drawings are included to provide a further understanding of the present disclosure and constitute a part of the specification, and are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation on the present disclosure. In the drawings:
[0018] Figure 1 is a structure schematic diagram of a solar cell in an embodiment of the present disclosure.
[0019] Figure 2 is a structure schematic diagram of a solar cell in another embodiment of the present disclosure.
[0020] Figure 3 is a flowchart of a solar cell preparation method according to an exemplary embodiment.
[0021] Figure 4 is a flowchart of another solar cell preparation method according to an exemplary embodiment.
[0022] Figure 5 is a preparation schematic diagram of a solar cell according to Figure 4 method.
[0023] Figure 6 is another preparation schematic diagram of a solar cell according to Figure 4 method.
[0024] Figure 7 is a preparation schematic diagram of a solar cell according to Figure 4Another preparation schematic of a solar cell is shown in the method.
[0025] Figure 8 According to Figure 4 Another preparation schematic of a solar cell is shown in the method.
[0026] Legend of reference signs
[0027] 1 - substrate; 11 - positive electrode region; 111 - first dielectric layer; 112 - first doped layer; 11a - first metallization region; 11b - first non-metallization region; 12 - negative electrode region; 121 - second dielectric layer; 122 - second doped layer; 12a - second metallization region; 12b - second non-metallization region; 13 - isolation region; 14 - passivation layer; 15 - titanium oxide layer; 21 - positive electrode; 22 - negative electrode. DETAILED DESCRIPTION
[0028] The specific embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the present disclosure, and are not intended to limit the present disclosure.
[0029] In the present disclosure, the orientation words such as "up, down, left, right" used without the opposite description are generally defined as the direction of the drawing surface, and "inner, outer" refers to the inner and outer of the related parts. In addition, the terms "first", "second" and the like are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.
[0030] With the rapid development of battery manufacturing technology, how to improve the electrical performance of solar cells has become one of the important research directions. In the related technology, the passivation effect of the solar cell is low, which further affects the electrical performance of the battery.
[0031] Therefore, in order to overcome the problems in the related art, the present disclosure provides a solar cell, which arranges the positive electrode region and the negative electrode region on the first surface of the substrate, so that the second surface of the substrate is not blocked by the grid lines, improves the short-circuit current of the battery, and improves the conversion efficiency of the battery. Covering the passivation layer on the positive electrode region can improve the open-circuit voltage, short-circuit current and conversion efficiency of the battery. On the basis of removing the passivation layer by laser opening film in the metallization region of the positive electrode region, covering the titanium oxide layer on the metallization region can repair the local defects of the substrate caused by laser opening film, and the passivation effect of the titanium oxide layer is improved relative to the original passivation layer. Covering the titanium oxide layer can further improve the minority carrier lifetime, open-circuit voltage and fill factor of the battery, thereby improving the photoelectric conversion efficiency and improving the electrical performance of the battery.
[0032] The present disclosure will be described below in conjunction with specific embodiments.
[0033] Figure 1is a structural schematic diagram of a solar cell in one embodiment of the present disclosure, as shown in Figure 1 The solar cell can include a substrate (1) and a positive electrode region (11) and a negative electrode region (12) on a first surface of the substrate (1), wherein the positive electrode region (11) includes a first dielectric layer (111) covering the substrate (1) and a first doped layer (112) covering the first dielectric layer (111), a first metallized region (11a) of the positive electrode region (11) covers a titanium oxide layer (15) on a corresponding region of the first doped layer (112), and a positive electrode (21) is printed on the titanium oxide layer (15); a first non-metallized region (11b) of the positive electrode region (11) covers a passivation layer (14) on a corresponding region of the first doped layer (112), and a second surface of the substrate (1) covers the passivation layer (14).
[0034] The solar cell can be a BC (Back Contact) cell, and the first surface of the substrate can be a back surface. The substrate can be a semiconductor material doped with an N-type doping element, which can include any one of a phosphorus element, an arsenic element, and an antimony element. The substrate can be a single crystal silicon, a polycrystalline silicon, or an amorphous silicon. The thickness of the substrate can be 100 μm-180 μm, and preferably 130 μm-150 μm. The positive electrode region is a region doped with a P-type element and corresponding to a positive electrode, and the negative electrode region is a region doped with an N-type element and corresponding to a negative electrode. The P-type element can include any one of a boron element, an indium element, and a gallium element.
[0035] In the positive electrode region, the first dielectric layer can be a silicon oxide layer, which can achieve quantum tunneling of a majority carrier. The first doped layer can be a polycrystalline silicon layer doped with a P-type element, which can enable charge transmission within the cell. The thickness of the first doped layer can be 100 nm-400 nm, for example, 100 nm, 250 nm, or 400 nm. The first metallized region includes a region of the positive electrode region directly contacting the positive electrode, and the first non-metallized region includes a region of the positive electrode region not directly contacting the positive electrode. A pre-designed patterned structure is formed on the surface of the first doped layer corresponding to the first metallized region by laser etching. The first metallized region covers a titanium oxide layer on a corresponding region of the first doped layer, and the covering method includes: first, covering a passivation layer on the corresponding region of the first doped layer of the first metallized region, then removing the passivation layer covering the region by laser during electrode printing, and finally covering a titanium oxide layer on the corresponding region of the first metallized region. Meanwhile, the first non-metallized region and the second surface of the substrate are both covered with a passivation layer to improve the fill factor and short-circuit current of the cell and to improve the photoelectric conversion efficiency. The second surface of the substrate is a light-receiving surface that can receive solar incident light.
[0036] The technical solution can arrange the positive electrode area and the negative electrode area on the first surface of the substrate, so that the second surface of the substrate is not blocked by the grid lines, the short-circuit current of the battery is improved, and the conversion efficiency of the battery is improved. Covering the passivation layer on the positive electrode area can improve the open-circuit voltage, short-circuit current and conversion efficiency of the battery. On the basis of removing the passivation layer by laser opening film in the metallization area of the positive electrode area, covering the titanium oxide layer on the metallization area can repair the local defects of the substrate caused by laser opening film, and the passivation effect of the titanium oxide layer relative to the original passivation layer is improved. Covering the titanium oxide layer can further improve the minority carrier lifetime, open-circuit voltage and fill factor of the battery, thereby improving the photoelectric conversion efficiency and improving the electrical performance of the battery.
[0037] The following table is the test results of the electrical performance of a plurality of groups of batteries after electrode sintering. As shown in Table 1, the electrical performance includes photoluminescence gray value, minority carrier lifetime, open-circuit voltage and fill factor. Among them, the photoluminescence gray value is used to measure the local defects of the substrate such as impurities, hidden cracks, etc., wherein the higher the photoluminescence gray value, the fewer the local defects of the substrate; the minority carrier lifetime, open-circuit voltage and fill factor are used to measure the photoelectric conversion efficiency of the battery, the longer the minority carrier lifetime, the higher the open-circuit voltage, the larger the fill factor, and the higher the photoelectric conversion efficiency. In Table 1, the ① group of batteries directly performs electrode printing and sintering after covering the passivation layer on the corresponding area of the first doped layer in the first metallization area, the ② group of batteries performs electrode printing and sintering after removing the passivation layer covering the first metallization area by laser, and the ③ group of batteries performs electrode printing and sintering after covering the titanium oxide layer after covering the passivation layer and removing the passivation layer by laser.
[0038] Table 1
[0039]
[0040] Referring to Table 1, the photoluminescence gray value of the battery in group ① (directly printing and sintering electrodes after covering the passivation layer) is 32531 pixels, the minority carrier lifetime is 4132.5 μs, the open circuit voltage is 740.5 mV, and the fill factor is 86%; the photoluminescence gray value of the battery in group ② (printing and sintering electrodes after covering the passivation layer and laser removing the passivation layer) is 25314 pixels, the minority carrier lifetime is 1932 μs, the open circuit voltage is 721.9 mV, and the fill factor is 84.1%; the photoluminescence gray value of the battery in group ③ (printing and sintering electrodes after covering the passivation layer and laser removing the passivation layer, and then covering the titanium oxide layer) is 34260 pixels, the minority carrier lifetime is 4330.5 μs, the open circuit voltage is 742 mV, and the fill factor is 86.4%. It can be seen that covering the titanium oxide layer in the metallized area, the titanium oxide can repair the laser damage caused by laser opening the film, and the photoluminescence gray value is improved. At the same time, the minority carrier lifetime, the open circuit voltage and the fill factor of the battery covered with the titanium oxide layer are all improved, and the photoelectric conversion efficiency of the battery is improved.
[0041] In some embodiments, as shown in FIG. 1, the negative electrode area (12) can include a second dielectric layer (121) covering the substrate (1) and a second doped layer (122) covering the second dielectric layer (121); the second metallized area (12a) and the second non-metallized area (12b) of the negative electrode area (12) are both covered with a passivation layer (14) in the corresponding area of the second doped layer (122), and the second metallized area (12a) is printed with a negative electrode (22) in the corresponding area of the passivation layer (14). Figure 2
[0042] In the negative electrode area, the second dielectric layer can be a silicon oxide layer, which can realize quantum tunneling of majority carriers. The second doped layer can be a polysilicon layer doped with an N-type element, which can enable charge transmission within the battery. The thickness of the second doped layer can be 100 nm-400 nm, for example, 100 nm, 250 nm, or 400 nm. The second metallized area includes the area of the negative electrode area that directly contacts the negative electrode, and the second non-metallized area includes the area of the negative electrode area that does not directly contact the negative electrode. A pre-designed patterned structure is formed on the surface of the second doped layer corresponding to the second metallized area by laser etching. In this way, covering the passivation layer in the negative electrode area can improve the open circuit voltage, short circuit current, and conversion efficiency of the battery.
[0043] In some embodiments, the thickness of the titanium oxide layer (15) can be 30nm-80nm, for example, 30nm, 40nm, 50nm, 60nm, 70nm or 80nm. This avoids the situation where the thickness of the titanium oxide layer is too low (less than 30nm) and fails to meet the passivation requirements of the battery, and also avoids the situation where the passivation effect of titanium oxide no longer improves when the thickness of the titanium oxide layer is too high (greater than 80nm), thereby increasing the manufacturing cost of the battery.
[0044] In some embodiments, the positive electrode (21) can be an aluminum electrode and the negative electrode (22) can be a silver electrode.
[0045] The aluminum electrode can penetrate the titanium oxide layer through a sintering process to contact the substrate corresponding to the first metallization region. The silver electrode can penetrate the passivation layer through a sintering process to contact the substrate corresponding to the second metallization region. Both aluminum and silver electrodes have good electrical conductivity, which is beneficial for electron conduction. Replacing the positive electrode with an aluminum electrode can reduce the battery's production cost.
[0046] In some embodiments, such as Figure 2 As shown, the first surface of the substrate (1) may also include an isolation region (13), which is located between the positive electrode region (11) and the negative electrode region (12), and the passivation layer (14) also covers the isolation region (13).
[0047] The isolation area can be a textured surface after polishing and texturing. This textured surface can prevent the positive and negative electrode areas from contacting each other, thus providing insulation and improving the reliability of the battery.
[0048] In some embodiments, the passivation layer (14) includes an aluminum oxide layer and a silicon nitride layer, the silicon nitride layer covering the aluminum oxide layer.
[0049] The alumina layer enhances the surface electric field of the semiconductor, reduces the recombination rate of electrons and holes, and improves the photoelectric conversion efficiency of the battery. The silicon nitride layer reduces the reflectivity of the battery surface, thereby increasing light absorption and conversion efficiency.
[0050] In some embodiments, the thickness of the aluminum oxide layer can be 2 nm-15 nm, for example, 2 nm, 5 nm, 8 nm, 11 nm, or 15 nm. The thickness of the silicon nitride layer can be 60 nm-90 nm, for example, 60 nm, 70 nm, 80 nm, or 90 nm. In this way, it can be avoided that the thickness of the aluminum oxide layer or the silicon nitride layer is set too low (the thickness of the aluminum oxide layer is less than 2 nm or the thickness of the silicon nitride layer is less than 60 nm) to meet the passivation requirements of the battery, and it can also be avoided that the thickness of the aluminum oxide layer or the silicon nitride layer is set too high (the thickness of the aluminum oxide layer is greater than 15 nm or the thickness of the silicon nitride layer is greater than 90 nm) so that the passivation effect of the passivation layer is no longer improved, thereby increasing the preparation cost of the battery.
[0051] Figure 3 is a flow chart of a solar cell preparation method according to an exemplary embodiment, as shown in Figure 2 , the solar cell preparation method can include the following steps:
[0052] In step S301, a first dielectric layer and a first doped layer are sequentially formed on a first region of a first surface of a substrate.
[0053] Among them, the target silicon wafer to be prepared can be polished to form a substrate, the target silicon wafer can be a silicon wafer with a resistivity of 1.5 -2.5 , the polishing solution can be a sodium hydroxide solution with a concentration of 45%, and the substrate surface has a light-trapping structure of a pyramid texture with a base height of 10 μm-20 μm. The first surface of the substrate can be a back surface, and the first region can be a pre-set positive electrode region.
[0054] In some embodiments, a first dielectric layer can be formed on the first region, an amorphous silicon layer can be deposited on the first dielectric layer, and boron elements can be doped in the amorphous silicon layer based on a boron diffusion process to form a first doped layer.
[0055] Among them, the first dielectric layer can be a silicon oxide layer, the first dielectric layer can be formed on the first region by a thermal oxidation method, the amorphous silicon layer can be deposited by any one of a low pressure chemical vapor deposition (LPCVD), a plasma enhanced chemical vapor deposition (PECVD), and a physical vapor deposition (PVD), the temperature of the boron diffusion process is set to 900°C-1000°C, and the boron source of the boron diffusion process can use boron chloride or boron bromide, which is not specifically limited by the present disclosure.
[0056] In step S302, the first doped layer is subjected to laser patterning.
[0057] The first doped layer can be subjected to laser patterning processing according to a preset pattern of the positive electrode area. The laser can be a pulsed laser, which can be green light or ultraviolet light. The pulse energy of the pulsed laser is 70 μJ-130 μJ. The scanning speed of the pulsed laser is greater than or equal to 60 m / s. The frequency of the pulsed laser can be 500 kHz. The spot diameter of the pulsed laser can be 100 μm-300 μm.
[0058] In step S303, a passivation layer is covered on the first doped layer and the second surface of the substrate.
[0059] The second surface of the substrate can be a light-receiving surface. The passivation layer can include an aluminum oxide layer and a silicon nitride layer.
[0060] In some embodiments, the aluminum oxide layer can be deposited based on an atomic layer deposition (ALD) process, and the silicon nitride layer can be deposited on the aluminum oxide layer to form the passivation layer.
[0061] The deposition thickness of the aluminum oxide layer can be 2 nm-15 nm, and the thickness of the silicon nitride layer can be 60 nm-90 nm. In addition, the silicon nitride layer can be deposited based on a PECVD process. It should be noted that the specific implementation steps of the ALD process and the PECVD process can refer to the implementation steps of related processes in the prior art, which will not be described here.
[0062] In step S304, the passivation layer on the first metallization area of the first region is removed.
[0063] The first metallization area includes a region in the positive electrode area that directly contacts the positive electrode. The passivation layer on the first metallization area can be removed by a ultraviolet femtosecond laser. The laser energy of the ultraviolet femtosecond laser can be 30 μJ-120 μJ, and the laser spot diameter can be 120 μm-150 μm.
[0064] In step S305, titanium oxide is deposited on the first metallization area to form a titanium oxide layer.
[0065] In some embodiments, titanium oxide can be deposited on the first metallization area based on a physical vapor deposition process.
[0066] The deposition thickness of the titanium oxide layer is 30 nm-80 nm. The specific implementation steps of the physical vapor deposition process can refer to the implementation steps of related processes in the prior art, which will not be described here.
[0067] In step S306, a positive electrode is printed on the titanium oxide layer to form a positive electrode area.
[0068] The positive electrode can be an aluminum electrode. After the positive electrode is printed, the positive electrode region can be formed by a laser-assisted sintering process. The specific implementation steps of the laser-assisted sintering process can refer to the implementation steps of the related process in the prior art, and will not be described here.
[0069] In step S307, a negative electrode region is formed on the second region on the first surface of the substrate to obtain a solar cell.
[0070] The above technical solution can arrange the positive electrode region and the negative electrode region on the first surface of the substrate, so that the second surface of the substrate is not blocked by the grid lines, the short-circuit current of the cell is improved, and the conversion efficiency of the cell is improved. Covering the passivation layer on the positive electrode region can improve the open-circuit voltage, short-circuit current and conversion efficiency of the cell. On the basis of removing the passivation layer by laser opening film in the metallization region of the positive electrode region, covering the titanium oxide layer on the metallization region can repair the local defects of the substrate caused by laser opening film. At the same time, the passivation effect of the titanium oxide layer is improved compared with the original passivation layer. Covering the titanium oxide layer can further improve the minority carrier lifetime, open-circuit voltage and fill factor of the cell, thereby improving the photoelectric conversion efficiency and the electrical performance of the cell.
[0071] In some embodiments, the above step S307 can include:
[0072] S3071, laser patterning processing is performed on the second region.
[0073] The second region can be a preset negative electrode region. The laser patterning processing can be performed on the substrate of the second region according to the preset pattern of the negative electrode region. The laser can be a pulsed laser, which can be green light or ultraviolet light. The pulse energy of the pulsed laser can be 70μJ-130μJ. The scanning speed of the pulsed laser can be greater than or equal to 60m / s. The frequency of the pulsed laser can be 500kHz. The spot diameter of the pulsed laser can be 100μm-300μm.
[0074] S3072, a second dielectric layer and a second doped layer are sequentially formed on the second region.
[0075] The second dielectric layer can be a silicon oxide layer. The second dielectric layer can be formed on the second region by a thermal oxidation method. An amorphous silicon layer can be deposited on the second dielectric layer by any one of the gas deposition processes of LPCVD, PECVD and PVD. Phosphorus elements can be doped in the amorphous silicon layer by a phosphorus diffusion process to form a second doped layer. The temperature of the phosphorus diffusion process is set to 800℃-1000℃. The phosphorus source of the phosphorus diffusion process can be phosphorus oxychloride.
[0076] S3073, a passivation layer is covered on the second doped layer.
[0077] The passivation layer can be formed by depositing an aluminum oxide layer based on an ALD process and depositing a silicon nitride layer based on a PECVD process on the aluminum oxide layer, the deposition thickness of the aluminum oxide layer can be 2 nm-15 nm, and the thickness of the silicon nitride layer can be 60 nm-90 nm.
[0078] S3074, printing a negative electrode on the second metallization area pre-divided in the second area to form a negative electrode area.
[0079] The second metallization area includes a region in the negative electrode area where the passivation layer directly contacts the negative electrode, and the negative electrode can be a silver electrode. After printing the negative electrode, the negative electrode area can be formed by a laser-assisted sintering process. The specific implementation steps of the laser-assisted sintering process can refer to the implementation steps of related processes in the prior art, which will not be described here.
[0080] In some embodiments, before covering the passivation layer on the first doped layer and the second surface of the substrate, the method further comprises: texturing the isolation area on the first surface of the substrate and the second surface of the substrate.
[0081] The isolation area is located between the first area and the second area. After texturing, the textured surface structure is a pyramid texture, which can reduce the surface reflectivity of the battery and increase the absorption of sunlight. The height of the base of the pyramid can be 10-20 μm, for example, it can be 10 μm, 15 μm, or 20 μm.
[0082] Figure 4 is a flow chart of another solar cell preparation method according to an exemplary embodiment, as shown in Figure 4 The method comprises:
[0083] S401, forming a first dielectric layer on a first area of a first surface of a substrate, and depositing an amorphous silicon layer on the first dielectric layer.
[0084] The first surface of the substrate can be a back surface, and the first area can be a predetermined positive electrode area. The first dielectric layer can be a silicon oxide layer, which can be formed on the first area by a thermal oxidation method. The amorphous silicon layer can be deposited by any one of the gas deposition processes of LPCVD, PECVD, and PVD.
[0085] S402, doping boron elements in the amorphous silicon layer based on a boron diffusion process to form a first doped layer.
[0086] The temperature of the boron diffusion process is set to 900-1000°C. The boron source of the boron diffusion process can use boron chloride or boron bromide, which is not limited in the present disclosure. The first doped layer formed by Figure 5 is shown.
[0087] S403, laser patterning processing is performed on the second region of the first surface of the substrate.
[0088] The second region can be a preset negative electrode region, the laser can be a pulse laser, green light or ultraviolet light can be used, the pulse energy of the pulse laser is 70 μJ-130 μJ, the scanning speed of the pulse laser is greater than or equal to 60 m / s, the frequency of the pulse laser can be 500 kHz, and the spot diameter of the pulse laser can be 100 μm-300 μm. In addition, after laser patterning processing, the BSG (Boro Silicate Glass, borosilicate glass) generated by laser patterning can be removed by using an HF acid solution with a concentration of 49%, and the laser damage can be removed by using a sodium hydroxide solution with a concentration of 45%.
[0089] S404, a second medium layer and a second doped layer are sequentially formed on the second region.
[0090] The second medium layer can be a silicon oxide layer, the second medium layer can be formed on the second region by a thermal oxidation method, an amorphous silicon layer can be deposited on the second medium layer by any one of the gas deposition processes of LPCVD, PECVD and PVD, and phosphorus elements can be doped in the amorphous silicon layer by a phosphorus diffusion process to form a second doped layer, the temperature of the phosphorus diffusion process is set to 800-1000 ℃, and the phosphorus source of the phosphorus diffusion process can use phosphorus oxychloride. The second doped layer formed by Figure 6 is shown.
[0091] S405, laser patterning processing is performed on the first doped layer.
[0092] The first doped layer can be laser patterned according to a preset pattern of the positive electrode region, the laser can be a pulse laser, green light or ultraviolet light can be used, the pulse energy of the pulse laser is 70 μJ-130 μJ, the scanning speed of the pulse laser is greater than or equal to 60 m / s, the frequency of the pulse laser can be 500 kHz, and the spot diameter of the pulse laser can be 100 μm-300 μm. In addition, after laser patterning processing, the PSG (Phospho Silicate Glass, phosphosilicate glass) generated by laser patterning can be removed by using an HF acid solution with a concentration of 49%, and the laser damage can be removed by using a sodium hydroxide solution with a concentration of 45%.
[0093] S406, texturing is performed on the isolation region of the first surface of the substrate and the second surface of the substrate.
[0094] The isolation region is located between the first region and the second region. The textured surface structure after texturing is a pyramid textured surface, and the height of the tower base of the pyramid is 10 μm-20 μm.
[0095] S407, covering a passivation layer on the first doped layer, the second doped layer, the isolation region and the second surface of the substrate.
[0096] The second surface of the substrate can be a light-receiving surface, and the passivation layer can include an aluminum oxide layer and a silicon nitride layer. The aluminum oxide layer can be deposited based on an ALD process, and the silicon nitride layer can be deposited on the aluminum oxide layer based on a PECVD process to form the passivation layer. The deposition thickness of the aluminum oxide layer can be 2-15 nm, and the thickness of the silicon nitride layer can be 60-90 nm. The covered passivation layer is shown in Figure 7 .
[0097] S408, removing the passivation layer on the first metallization region of the first region pre-divided.
[0098] The first metallization region includes an area in the positive electrode region directly in contact with the positive electrode, and the passivation layer on the first metallization region can be removed by a ultraviolet femtosecond laser. The laser energy of the ultraviolet femtosecond laser can be 30-120 μJ, and the laser spot diameter can be 120-150 μm.
[0099] S409, depositing titanium oxide on the first metallization region based on a physical vapor deposition process to form a titanium oxide layer.
[0100] The deposition thickness of the titanium oxide layer is 30-80 nm.
[0101] S410, printing a positive electrode on the titanium oxide layer.
[0102] The positive electrode can be an aluminum electrode.
[0103] S411, printing a negative electrode on the second metallization region of the second region pre-divided.
[0104] The second metallization region includes an area in the negative electrode region directly in contact with the negative electrode, and the negative electrode can be a silver electrode. The formed solar cell is shown in Figure 8 .
[0105] By using the above method, the positive electrode region and the negative electrode region can be arranged on the first surface of the substrate, so that the second surface of the substrate is not blocked by the grid lines, the short-circuit current of the battery is improved, and the conversion efficiency of the battery is improved. Covering the passivation layer on the positive electrode region can improve the open-circuit voltage, short-circuit current and conversion efficiency of the battery. On the basis of removing the passivation layer by laser opening film in the metallized region of the positive electrode region, covering the titanium oxide layer on the metallized region can repair the local defects of the substrate caused by laser opening film, and the passivation effect of the titanium oxide layer is improved compared with the original passivation layer. Covering the titanium oxide layer can further improve the minority carrier lifetime, open-circuit voltage and fill factor of the battery, thereby improving the photoelectric conversion efficiency and improving the electrical performance of the battery. In addition, replacing the positive electrode with a silver electrode with an aluminum electrode can reduce the production cost of the battery.
[0106] It should be noted that the above Figure 3 The related description of each step in the embodiments shown in the above embodiments can refer to the description of the related steps in the foregoing embodiments, and will not be described here.
[0107] In addition, for the above method embodiments, in order to simply describe, they are all expressed as a series of action combinations, but those skilled in the art should know that the present application is not limited by the action sequence described, for example, the above steps S410 and S411 are not limited to the step sequence shown in the current embodiment, and step S411 can be performed first, and then step S410 is performed, or steps S410 and S411 are performed at the same time. Secondly, those skilled in the art should know that the embodiments described in the specification all belong to preferred embodiments, and the actions and modules involved are not necessarily necessary for the present application.
[0108] The preferred embodiments of the present application are described in detail above in combination with the drawings, but the present application is not limited to the specific details in the above embodiments. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, and these simple modifications all belong to the protection scope of the present application.
[0109] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, various possible combination manners are not described again in the present application.
[0110] In addition, various different embodiments of the present application can also be combined in any manner, as long as they do not deviate from the idea of the present application, and they should also be considered as disclosed by the present application.
Claims
1. A solar cell, characterized by, The solar cell comprises a substrate (1) and a positive electrode area (11) and a negative electrode area (12) on a first surface of the substrate (1); the positive electrode area (11) comprises a first dielectric layer (111) and a first doped layer (112) on the substrate (1), and the first doped layer (112) is on the first dielectric layer (111); A first metallized area (11a) of the positive electrode area (11) is covered with a titanium oxide layer (15) on a corresponding area of the first doped layer (112), and a positive electrode (21) is printed on the titanium oxide layer (15); a first non-metallized area (11b) of the positive electrode area (11) is covered with a passivation layer (14) on a corresponding area of the first doped layer (112), and a second surface of the substrate (1) is covered with the passivation layer (14).
2. The solar cell according to claim 1, characterized in that, The negative electrode area (12) comprises a second dielectric layer (121) and a second doped layer (122) on the substrate (1), and the second doped layer (122) is on the second dielectric layer (121); A second metallized area (12a) and a second non-metallized area (12b) of the negative electrode area (12) are both covered with a passivation layer (14) on a corresponding area of the second doped layer (122), and the second metallized area (12a) is printed with a negative electrode (22) on a corresponding area of the passivation layer (14).
3. The solar cell according to claim 1, characterized in that, The thickness of the titanium oxide layer (15) is 30-80 nm.
4. The solar cell of claim 1, wherein The positive electrode (21) is an aluminum electrode.
5. The solar cell of claim 1, wherein The first dielectric layer (111) is a silicon oxide layer.
6. The solar cell of claim 1, wherein The first doped layer (112) is a polycrystalline silicon layer doped with a P-type element.
7. The solar cell of claim 1, wherein The back surface of the substrate (1) further comprises an isolation area (13) between the positive electrode area (11) and the negative electrode area (12). The passivation layer (14) further covers the isolation area (13).
8. The solar cell of claim 7, wherein, The first surface of the substrate (1) and the isolation area (13) are in a pyramid suede structure, and the height of the base of the pyramid is 10-20 μm.
9. Solar cell according to any of claims 1-8, characterized in that, The passivation layer (14) comprises an aluminum oxide layer and a silicon nitride layer, and the silicon nitride layer is on the aluminum oxide layer.
10. The solar cell of claim 9, wherein, The thickness of the aluminum oxide layer is 2-15 nm, and the thickness of the silicon nitride layer is 60-90 nm.