Method for passivating edge of half solar cell

Abstract

The invention discloses a method for passivating the edge of a half solar cell, and belongs to the technical field of silicon solar cells. The method comprises the following steps: cutting a battery piece to obtain half battery pieces, placing the half battery pieces in a cavity of chemical vapor deposition equipment, and carrying out vacuum preheating treatment; then introducing ammonia gas and laughing gas to purge the cutting surface of the half battery piece, and carrying out ionization pretreatment, nitrogen blowing and vacuum pumping; carrying TMA molecules and water vapor through carrier gas to form a first aluminum oxide film layer; carrying TMA molecules and laughing gas through carrier gas to form a second aluminum oxide film layer; and then introducing ammonia gas and laughing gas to purge the cutting surface of the half battery piece, and then carrying out ionization pretreatment, nitrogen blowing, vacuumizing and annealing to obtain the solar half battery piece with the passivated edge. According to the method, the uniformity and the passivation effect of the aluminum oxide film layer are improved, the winding plating range is reduced, and the pseudo soldering proportion is reduced.

Description

Technical Field

[0001] This invention relates to the field of silicon solar cell technology, and in particular to a method for passivating the edge of a solar cell half-cell. Background Technology

[0002] Currently, mainstream solar cell production uses large-size silicon wafers such as 182mm×182mm, 182mm×210mm, and 210mm×210mm. To improve module power, the industry commonly uses half-cell module technology, which cuts full-cell solar cells into half-cells, such as 182mm×91mm, 182mm×105mm, and 210mm×105mm, using lasers or other methods. This reduces the current passing through each main busbar to half of the original, thus reducing the power loss of half-cell modules to one-quarter of that of full-cell modules. Compared to full-cell modules, half-cell modules can improve power efficiency by 5%-10% and have almost become the standard technology for large-size solar cell modules.

[0003] Laser cutting is commonly used for half-cell cutting of solar cells. However, this inevitably causes structural mechanical damage at the cutting point, preventing stress release. After half-cell cutting, the exposed silicon wafer at the cut surface becomes a strong damage and recombination center, ultimately reducing the cell's conversion efficiency by 0.2%-0.3%. Therefore, alternative solutions are needed to address this defect. Currently, the mainstream technology involves cutting the cells in half after screen printing and LECO (laser-assisted sintering) processes, stacking them, and then depositing an alumina film on the cut surface for passivation. Half-cell edge passivation technology has been gradually applied to TOPCon cell production. 182mm×182mm-72 module power gain reaches over 5W, translating to a cell conversion efficiency gain of over 0.21%. However, during alumina deposition, gaps inevitably exist between cells, causing alumina to coat both the front and back of the cell. This affects the appearance of the half-cell after edge passivation and increases the proportion of poor solder joints during module welding. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for edge passivation of solar half-cell cells. This invention involves plasma treatment of the cut surface of the laser-cut cell and the alumina film deposited on the cut surface to achieve superior uniformity and passivation effect of the alumina film. By optimizing the half-cell edge passivation process, the passivation effect of the alumina film is guaranteed while reducing the area of ​​the alumina film deposition process, thereby lowering the proportion of incomplete solder joints during module welding.

[0005] The technical solution of the present invention is as follows: A method for passivating the edge of a solar cell half-cell, the method comprising the following steps: S1 The battery cell is cut into half-cells, stacked so that the cut surfaces of the half-cells are on the same plane, and placed in the cavity of the chemical vapor deposition equipment; the cut surfaces are parallel to the airflow direction set in the cavity; S2 Evacuate the cavity and heat it to the preset reaction temperature to perform vacuum preheating treatment on the battery cells; S3 Ammonia and nitrous oxide are introduced to purge the cut surface of half of the battery cell for ionization pretreatment, followed by nitrogen blowing and vacuuming. S4 deposits the first aluminum oxide film layer, specifically as follows: S4.1 Introduce a carrier gas carrying TMA molecules to saturate the TMA with the cut surface of the half-cell, followed by nitrogen blowing. S4.2 Then, a carrier gas carrying water vapor is introduced, so that the water vapor reacts with TMA to form alumina, followed by a second nitrogen purging; Repeat steps S4.1 and S4.2 50 to 80 times to form the first layer of alumina film. S5 deposits the second alumina film layer, specifically as follows: S5.1 Introduce a carrier gas carrying TMA molecules to saturate the TMA with the cut surface of the half-cell, followed by nitrogen blowing. S5.2 Ionization treatment with nitrous oxide followed by secondary nitrogen blowing; Repeat steps S5.1 and S5.2 50 to 80 times to form the second aluminum oxide film layer; S6 Introduces ammonia and nitrous oxide to purge the cut surface of the half-cell for ionization pretreatment, followed by nitrogen blowing, vacuuming, and then annealing to obtain a solar half-cell with passivated edges.

[0006] Further, in step S1, the half-cell is conveyed to the cavity of the chemical vapor deposition equipment via a carrier, with the cut surface of the half-cell exposed and the other surfaces not exposed; Step S1 further includes: placing a flow equalization component near the air inlet, wherein the flow equalization component has multiple parallel airflow channels inside, and the axis of the airflow channels is parallel to the cut surface of the half-cell battery cell.

[0007] Furthermore, in step S2, the temperature of the vacuum preheating treatment is 100-200 ℃, the vacuum degree is 10-30 mTorr, and the time is 30-60 min.

[0008] Further, in step S3, the flow rate of ammonia is 2000-5000 sccn, the flow rate of nitrous oxide is 1000-3000 sccm, and the on / off ratio is 3-5:50; the purging time is 5-10 s, and the reaction pressure is 100-180 Pa; the radio frequency power supply for the ionization pretreatment is 30-50 kHz, and the discharge power is 3000-8000 W; the flow rate of nitrogen purging is 10000-20000 sccm, and the time is 6-10 s; the vacuum degree is 10-30 mTorr.

[0009] Further, in step S4.1, the carrier gas is N2; the source tank temperature of the TMA is 50-60 ℃; the flow rate of the carrier gas carrying TMA molecules is 3000-8000 sccm, and the introduction time is 2-8 s; the nitrogen blowing flow rate is 10000-20000 sccm, and the time is 5-10 s. In step S4.2, the carrier gas is N2, the source tank temperature of the water vapor is 30-40 ℃, the flow rate of the carrier gas carrying the water vapor is 3000-5000 sccm, and the introduction time is 4-8 s; the flow rate of the secondary nitrogen blowing is 10000-20000 sccm, and the time is 6-10 s.

[0010] Furthermore, in step S4, the thickness of the first alumina film layer is 6~10 nm.

[0011] Further, in step S5.1, the carrier gas is N2, the source tank temperature of the TMA is 50-60 ℃; the flow rate of the carrier gas carrying the TMA molecules is 3000-8000 sccm, and the introduction time is 2-8 s; the flow rate of the nitrogen blowing is 10000-20000 sccm, and the time is 5-10 s; the flow rate of the secondary nitrogen blowing is 10000-20000 sccm, and the time is 6-10 s. In step S5.2, the flow rate of the nitrous oxide is 3000-6000 sccm, and the on / off ratio is 3-5:50; the radio frequency power supply for the ionization treatment is 30-50 kHz, the discharge power is 3000-8000 W, the time is 5-10 s, and the reaction pressure is 100-180 Pa; the flow rate of the secondary nitrogen blowing is 10000-20000 sccm, and the time is 6-10 s.

[0012] Furthermore, in step S5, the thickness of the second alumina film layer is 6~10 nm.

[0013] Further, in step S6, the flow rate of ammonia is 2000-4000 sccm, the flow rate of nitrous oxide is 1000-3000 sccm, and the on / off ratio is 3-5:50; the purging time is 5-10 s, and the reaction pressure is 100-180 Pa; the radio frequency power supply for the ionization pretreatment is 30-50 kHz, and the discharge power is 3000-8000 W; the nitrogen blowing flow rate is 10000-20000 sccm, and the time is 6-10 s; the vacuum degree is 10-30 mTorr.

[0014] Furthermore, in step S6, the annealing temperature is 280-400 ℃ and the time is 20-40 min.

[0015] The beneficial technical effects of this invention are as follows: After a solar cell is cut in half, dust and particulate matter easily adhere to the cut surface, and the flatness of the cut surface varies during actual production. This invention addresses this by subjecting the cut surface and the deposited alumina film layer of the laser-cut solar cell half-cell to plasma treatment. Through plasma ionization and electric field acceleration, ammonia and nitrous oxide generate a plasma medium under the coupling of electromagnetic forces. This plasma medium bombards and cleans the cut surface of the half-cell, resulting in a more uniform alumina film layer. Simultaneously, the ionization of ammonia and nitrous oxide generates H and OH bonds, respectively, allowing the cut surface of the half-cell to adsorb more OH and H bonds with stronger binding energy. The plasma treatment enhances field passivation and hydrogen passivation. Field passivation constructs an electric field in a specific direction on the surface, which effectively prevents carriers of the same polarity from approaching the surface, thereby reducing the probability of carrier recombination. Hydrogen passivation allows ionized hydrogen to occupy vacant dangling bonds, further reducing the probability of carrier recombination and improving minority carrier lifetime. Meanwhile, this invention optimizes the process of half-cell edge passivation deposition of alumina. Two alumina film layers are deposited. The first alumina film layer reacts with TMA and water vapor, allowing it to adsorb more H bonds and providing excellent hydrogen passivation. Due to the height difference between the metal grid lines after screen printing, the cells cannot be perfectly bonded together, inevitably creating gaps. Water vapor easily adheres to these gaps and is difficult to clean. Residual water causes direct contact between the two reaction sources in the ALD process, resulting in CVD reaction and causing plating around the non-cut surfaces of the cells. Severe plating around can lead to poor welding at the module ends, resulting in customer complaints. Therefore, this invention optimizes the half-cell edge passivation process. The second alumina film layer reacts with TMA and nitrous oxide, ensuring the chemical passivation effect of the alumina film layer without affecting its thickness and uniformity, reducing the plating area, and thus lowering the proportion of poor welds during module welding. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the solar cell half-cell being placed into the carrier according to the present invention. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0018] Example 1 A method for passivating the edge of a solar cell half-cell includes the following steps: S1 provides a chemical vapor deposition chamber, which includes upper and lower electrode plates and a carrier conveying device. The conveying device has several carriers that can hold half-cell solar cells. The carriers are provided with openings for the deposition film, and infrared lamp heating devices are located in the direction of the deposition film openings. The LECO (laser-assisted sintering) solar cells are cut in half, and the cut halves are stacked neatly in the carriers so that the cut surfaces of the half-cells are on the same plane (e.g., ...). Figure 1 As shown), the cut surface of half of the battery cell is fully exposed at the opening of the substrate deposition film layer, and the cut surface is parallel to the airflow direction in the cavity. The substrate is then transported to the chemical vapor deposition chamber by a conveying device.

[0019] S2 evacuates the cavity to a vacuum level of 10 mTorr and heats it to 150 ℃ to perform vacuum preheating treatment on half of the solar cell for 30 min.

[0020] S3 Introducing ammonia and nitrous oxide, maintaining constant chamber pressure: Ammonia and nitrous oxide are introduced into the chemical vapor deposition chamber, maintaining a constant chamber reaction pressure of 120 Pa, with an ammonia flow rate of 3000 sccm and a nitrous oxide flow rate of 2000 sccm, and an induction time of 5 s; Ammonia and nitrous oxide are introduced for plasma treatment: Ammonia and nitrous oxide are introduced into the chemical vapor deposition chamber for pre-ionization, wherein the flow rate of ammonia is 3000 sccm, the flow rate of nitrous oxide is 2000 sccm, the power supply time is 5 s, the radio frequency power supply is 40 kHz, the discharge power is 5000 W, the switching ratio is 5:50, and the reaction pressure is 120 Pa. Nitrogen purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 6 s. Vacuuming: The chemical vapor deposition chamber is evacuated to a vacuum level of 10 mTorr.

[0021] S4 deposits the first aluminum oxide film layer, specifically as follows: S4.1 Introducing TMA: TMA (trimethylaluminum) is carried into the chemical vapor deposition chamber by high-purity N2, so that TMA is saturated and adsorbed on the cut surface of the half-cell. The source tank temperature of TMA is 50 ℃, the flow rate of high-purity N2 carrying TMA is 5000 sccm, and the source time is 5 s. First purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 5 s. S4.2 Introducing water vapor: Water vapor (oxygen source) is carried into the chemical vapor deposition chamber by high-purity N2, so that the water vapor reacts with TMA adsorbed on the cut surface of the half-cell to form an alumina layer. The temperature of the water vapor source tank is 30°C, the flow rate of high-purity N2 carrying the water vapor is 3000 sccm, and the introducing time is 5s.

[0022] Secondary purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 6 s. Repeat steps S4.1 and S4.2 50 times to deposit an aluminum oxide film with a thickness of 6 nm on the cut surface of the half-cell.

[0023] S5 deposits the second alumina film layer, specifically as follows: S5.1 Introducing TMA: TMA (trimethylaluminum) is carried into the chemical vapor deposition chamber by high-purity N2, so that TMA is saturated and adsorbed on the cut surface of the half-cell. The source tank temperature of TMA is 50 ℃, the flow rate of high-purity N2 carrying TMA is 5000 sccm, and the source time is 5 s. First purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 5 s. S5.2 Introducing nitrous oxide and maintaining constant chamber pressure: Nitrous oxide is introduced into the chemical vapor deposition chamber, and the constant chamber reaction pressure is 120 Pa, wherein the flow rate of nitrous oxide is 5000 sccm, and the induction time is 5s; Nitrous oxide ionization: Nitrous oxide is introduced into the chemical vapor deposition chamber for ionization treatment. The flow rate of nitrous oxide is 5000 sccm, the power supply time is 5 s, the radio frequency power supply is 40 kHz, the discharge power is 5500 W, the switching ratio is 5:50, and the reaction pressure is 120 Pa. Secondary purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 6 s. Repeat steps S5.1 and S5.2 50 times to deposit an aluminum oxide film with a thickness of 6 nm on the cut surface of the half-cell.

[0024] S6 Introducing ammonia and nitrous oxide, maintaining constant chamber pressure: Ammonia and nitrous oxide are introduced into the chemical vapor deposition chamber, maintaining a constant chamber reaction pressure of 120 Pa, with an ammonia flow rate of 3000 sccm and a nitrous oxide flow rate of 2000 sccm, and an induction time of 5 s; Ammonia and nitrous oxide are introduced for plasma treatment: Ammonia and nitrous oxide are introduced into the high chemical vapor deposition chamber for pre-ionization, wherein the flow rate of ammonia is 3000 sccm, the flow rate of nitrous oxide is 2000 sccm, the power supply time is 5 s, the radio frequency power supply is 40 kHz, the discharge power is 5000 W, the switching ratio is 5:50, and the reaction pressure is 120 Pa. Nitrogen purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 6 s. Vacuuming: The chemical vapor deposition chamber is evacuated to a vacuum level of 10 mTorr.

[0025] S7 uses an infrared lamp to heat and irradiate the aluminum oxide film layer on the cut surface of the half-cell solar cell for annealing treatment. The annealing temperature is 330 ℃ and the annealing time is 30 min. After the annealing treatment, the chemical vapor deposition chamber is filled with N2 to atmospheric pressure, and the carrier exits the chamber to obtain an edge-passivated solar half-cell solar cell.

[0026] Example 2 A method for passivating the edge of a solar cell half-cell includes the following steps: S1 provides a chemical vapor deposition chamber, which includes upper and lower electrode plates and a carrier conveying device. The conveying device has several carriers that can hold half-cell solar cells. The carriers are provided with openings for the deposition film, and infrared lamp heating devices are located in the direction of the deposition film openings. The LECO (laser-assisted sintering) solar cells are cut in half, and the cut halves are stacked neatly in the carriers so that the cut surfaces of the half-cells are on the same plane (e.g., ...). Figure 1 As shown), the cut surface of half of the battery cell is fully exposed at the opening of the substrate deposition film layer, and the cut surface is parallel to the airflow direction in the cavity. The substrate is then transported to the chemical vapor deposition chamber by a conveying device.

[0027] S2 evacuates the cavity to a vacuum level of 10 mTorr and heats it to 150 ℃ to perform vacuum preheating treatment on half of the solar cell for 30 min.

[0028] S3 Introducing ammonia and nitrous oxide, maintaining constant chamber pressure: Ammonia and nitrous oxide are introduced into the chemical vapor deposition chamber, maintaining a constant chamber reaction pressure of 120 Pa, with an ammonia flow rate of 3000 sccm and a nitrous oxide flow rate of 2000 sccm, and an induction time of 5 s; Ammonia and nitrous oxide were introduced for plasma pretreatment: Ammonia and nitrous oxide were introduced into the high chemical vapor deposition chamber for pre-ionization, wherein the flow rate of ammonia was 3000 sccm, the flow rate of nitrous oxide was 2000 sccm, the power supply time was 5 s, the radio frequency power supply used was 40 kHz, the discharge power was 5000 W, the switching ratio was 5:50, and the reaction pressure was 120 Pa. Nitrogen purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 6 s. Vacuuming: The chemical vapor deposition chamber is evacuated to a vacuum level of 10 mTorr.

[0029] S4 deposits the first aluminum oxide film layer, specifically as follows: S4.1 Introducing TMA: TMA (trimethylaluminum) is carried into the chemical vapor deposition chamber by high-purity N2, so that TMA is saturated and adsorbed on the cut surface of the half-cell. The source tank temperature of TMA is 50 ℃, the flow rate of high-purity N2 carrying TMA is 5000 sccm, and the source time is 5 s. First purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 5 s. S4.2 Introducing water vapor: Water vapor (oxygen source) is carried into the chemical vapor deposition chamber by high-purity carrier gas N2, so that the water vapor reacts with TMA adsorbed on the cut surface of the half-cell battery to form an alumina layer. The temperature of the water vapor source tank is 30 ℃, the flow rate of high-purity N2 carrying water vapor is 3000 sccm, and the introducing time is 5 s. Secondary purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 6 s. Following steps S4.1 and S4.2 for 65 cycles, an aluminum oxide film with a thickness of 8 nm is deposited on the cut surface of the half-cell. S5 deposits the second alumina film layer, specifically as follows: S5.1 Introducing TMA: TMA (trimethylaluminum) is carried into the chemical vapor deposition chamber by high-purity N2, so that TMA is saturated and adsorbed on the cut surface of the half-cell. The source tank temperature of TMA is 50 ℃, the flow rate of high-purity N2 carrying TMA is 5000 sccm, and the source time is 5s. First purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 5s. S5.2 Introducing nitrous oxide and maintaining constant chamber pressure: Nitrous oxide is introduced into the chemical vapor deposition chamber, and the constant chamber reaction pressure is 120 Pa, wherein the flow rate of nitrous oxide is 5000 sccm, and the induction time is 5 s; Nitrous oxide ionization: Nitrous oxide is introduced into the chemical vapor deposition chamber for ionization treatment. The flow rate of nitrous oxide is 5000 sccm, the power supply time is 5 s, the radio frequency power supply is 40 kHz, the discharge power is 5500 W, the switching ratio is 5:50, and the reaction pressure is 120 Pa. Secondary purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 6 s. By repeating steps S5.1 and S5.2 65 times, an aluminum oxide film with a thickness of 8 nm is deposited on the cut surface of the half-cell.

[0030] S6 Introducing ammonia and nitrous oxide, maintaining constant chamber pressure: Ammonia and nitrous oxide are introduced into the chemical vapor deposition chamber, maintaining a constant chamber reaction pressure of 120 Pa, with an ammonia flow rate of 3000 sccm and a nitrous oxide flow rate of 2000 sccm, and an induction time of 5 s; Ammonia and nitrous oxide are introduced for plasma treatment: Ammonia and nitrous oxide are introduced into the high chemical vapor deposition chamber for pre-ionization, wherein the flow rate of ammonia is 3000 sccm, the flow rate of nitrous oxide is 2000 sccm, the power supply time is 5 s, the radio frequency power supply is 40 kHz, the discharge power is 5000 W, the switching ratio is 5:50, and the reaction pressure is 120 Pa. Nitrogen purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 6 s. Vacuuming: The chemical vapor deposition chamber is evacuated to a vacuum level of 10 mTorr.

[0031] S7 uses an infrared lamp to heat and irradiate the aluminum oxide film layer on the cut surface of the half-cell solar cell for annealing treatment. The annealing temperature is 330 ℃ and the annealing time is 30 min. After the annealing treatment, the chemical vapor deposition chamber is filled with N2 to atmospheric pressure, and the carrier exits the chamber to obtain an edge-passivated solar half-cell solar cell.

[0032] Example 3 A method for passivating the edge of a solar cell half-cell includes the following steps: S1 provides a chemical vapor deposition chamber, which includes upper and lower electrode plates and a carrier conveying device. The conveying device has several carriers that can hold half-cell solar cells. The carriers are provided with openings for the deposition film, and infrared lamp heating devices are located in the direction of the deposition film openings. The LECO (laser-assisted sintering) solar cells are cut in half, and the cut halves are stacked neatly in the carriers so that the cut surfaces of the half-cells are on the same plane (e.g., ...). Figure 1 As shown), the cut surface of half of the battery cell is fully exposed at the opening of the substrate deposition film layer, and the cut surface is parallel to the airflow direction in the cavity. The substrate is then transported to the chemical vapor deposition chamber by a conveying device.

[0033] S2 evacuates the cavity to a vacuum level of 10 mTorr and heats it to 150 °C to perform vacuum preheating treatment on half of the solar cell for 30 min.

[0034] S3 Introducing ammonia and nitrous oxide, maintaining constant chamber pressure: Ammonia and nitrous oxide are introduced into the chemical vapor deposition chamber, maintaining a constant chamber reaction pressure of 120 Pa, with an ammonia flow rate of 3000 sccm and a nitrous oxide flow rate of 2000 sccm, and an induction time of 5 s; Ammonia and nitrous oxide were introduced for plasma pretreatment: Ammonia and nitrous oxide were introduced into the high chemical vapor deposition chamber for pre-ionization, wherein the flow rate of ammonia was 3000 sccm, the flow rate of nitrous oxide was 2000 sccm, the power supply time was 5 s, the radio frequency power supply used was 40 kHz, the discharge power was 5000 W, the switching ratio was 5:50, and the reaction pressure was 120 Pa. Nitrogen purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 6 s. Vacuuming: The chemical vapor deposition chamber is evacuated to a vacuum level of 10 mTorr.

[0035] S4 deposits the first aluminum oxide film layer, specifically as follows: S4.1 Introducing TMA: TMA (trimethylaluminum) is carried into the chemical vapor deposition chamber by high-purity N2, so that TMA is saturated and adsorbed on the cut surface of the half-cell. The source tank temperature of TMA is 50 ℃, the flow rate of high-purity N2 carrying TMA is 5000 sccm, and the source time is 5 s. First purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 5 s. S4.2 Introducing water vapor: Water vapor (oxygen source) is carried into the chemical vapor deposition chamber by high-purity N2, so that the water vapor reacts with TMA adsorbed on the cut surface of the half-cell to form an alumina layer. The temperature of the water vapor source tank is 30°C, the flow rate of high-purity N2 carrying the water vapor is 3000 sccm, and the introducing time is 5 s.

[0036] Secondary purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 6 s. Following steps S4.1 and S4.2 for 80 cycles, an aluminum oxide film with a thickness of 10 nm is deposited on the cut surface of the half-cell. S5 deposits the second alumina film layer, specifically as follows: S5.1 Introducing TMA: TMA (trimethylaluminum) is carried into the chemical vapor deposition chamber by high-purity N2, so that TMA is saturated and adsorbed on the cut surface of the half-cell. The source tank temperature of TMA is 50 ℃, the flow rate of high-purity N2 carrying TMA is 5000 sccm, and the source time is 5 s. First purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 5s. S5.2 Introducing nitrous oxide and maintaining constant chamber pressure: Nitrous oxide is introduced into the chemical vapor deposition chamber, and the constant chamber reaction pressure is 120 Pa, wherein the flow rate of nitrous oxide is 5000 sccm, and the induction time is 5 s; Nitrous oxide ionization: Nitrous oxide is introduced into the chemical vapor deposition chamber for ionization treatment. The flow rate of nitrous oxide is 5000 sccm, the induction time is 5 s, the radio frequency power supply is 40 kHz, the discharge power is 5500 W, the on / off ratio is 5:50, and the reaction pressure is 120 Pa. Secondary purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 6 s. By repeating steps S5.1 and S5.2 80 times, an aluminum oxide film with a thickness of 10 nm is deposited on the cut surface of the half-cell.

[0037] S6 Introducing ammonia and nitrous oxide, maintaining constant chamber pressure: Ammonia and nitrous oxide are introduced into the chemical vapor deposition chamber, maintaining a constant chamber reaction pressure of 120 Pa, with an ammonia flow rate of 3000 sccm and a nitrous oxide flow rate of 2000 sccm, and an induction time of 5 s; Ammonia and nitrous oxide are introduced for plasma treatment: Ammonia and nitrous oxide are introduced into the high chemical vapor deposition chamber for pre-ionization, wherein the flow rate of ammonia is 3000 sccm, the flow rate of nitrous oxide is 2000 sccm, the power supply time is 5 s, the radio frequency power supply is 40 kHz, the discharge power is 5000 W, the switching ratio is 5 / 50, and the reaction pressure is 120 Pa. Nitrogen purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 6 s. Vacuuming: The chemical vapor deposition chamber is evacuated to a vacuum level of 10 mTorr.

[0038] S7 uses an infrared lamp to heat and irradiate the aluminum oxide film layer on the cut surface of the half-cell solar cell for annealing treatment. The annealing temperature is 330 ℃ and the annealing time is 30 min. After the annealing treatment, the chemical vapor deposition chamber is filled with N2 to atmospheric pressure, and the carrier exits the chamber to obtain an edge-passivated solar half-cell solar cell.

[0039] Comparative Example 1 Half a battery cell that has not undergone any treatment.

[0040] Comparative Example 2 A method for passivating the edge of a solar cell half-cell includes the following steps: S1 provides a chemical vapor deposition chamber, which includes upper and lower electrode plates and a carrier conveying device. The conveying device has several carriers that can hold half-cell solar cells. The carriers are provided with openings for the deposition film, and infrared lamp heating devices are located in the direction of the deposition film openings. The LECO (laser-assisted sintering) solar cells are cut in half, and the cut halves are stacked neatly in the carriers so that the cut surfaces of the half-cells are on the same plane (e.g., ...). Figure 1As shown), the cut surface of half of the battery cell is fully exposed at the opening of the substrate deposition film layer, and the cut surface is parallel to the airflow direction in the cavity. The substrate is then transported to the chemical vapor deposition chamber by a conveying device.

[0041] S2 evacuates the cavity to a vacuum level of 10 mTorr and heats it to 150 ℃ to perform vacuum preheating treatment on half of the solar cell for 30 min.

[0042] S3 Introducing ammonia and nitrous oxide, maintaining constant chamber pressure: Ammonia and nitrous oxide are introduced into the chemical vapor deposition chamber, maintaining a constant chamber reaction pressure of 120 Pa, with an ammonia flow rate of 3000 sccm and a nitrous oxide flow rate of 2000 sccm, and an induction time of 5 s; Ammonia and nitrous oxide were introduced for plasma pretreatment: Ammonia and nitrous oxide were introduced into the high chemical vapor deposition chamber for pre-ionization treatment. The flow rate of ammonia was 3000 sccm, the flow rate of nitrous oxide was 2000 sccm, the power supply time was 5 s, the radio frequency power supply was 40 kHz, the discharge power was 5000 W, the switching ratio was 5:50, and the reaction pressure was 120 Pa. Nitrogen purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 6 s. Vacuuming: The chemical vapor deposition chamber is evacuated to a vacuum level of 10 mTorr.

[0043] S4 deposits the first aluminum oxide film layer, specifically as follows: S4.1 Introducing TMA: TMA (trimethylaluminum) is carried into the chemical vapor deposition chamber by high-purity N2, so that TMA is saturated and adsorbed on the cut surface of the half-cell. The source tank temperature of TMA is 50°C, the flow rate of high-purity N2 carrying TMA is 5000 sccm, and the source time is 5 s. First purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 5 s. S4.2 Introducing water vapor: Water vapor (oxygen source) is carried into the chemical vapor deposition chamber by high-purity N2, so that the water vapor reacts with TMA adsorbed on the cut surface of the half-cell battery to form an alumina layer. The temperature of the water vapor source tank is 30°C, the flow rate of high-purity N2 carrying the oxygen source water vapor is 3000 sccm, and the introducing time is 5 s. Secondary purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 6 s. Repeat steps S4.1 and S4.2 100 times to deposit an aluminum oxide film with a thickness of 12 nm on the cut surface of the half-cell. S5 deposits the second alumina film layer, specifically as follows: S5.1 Introducing TMA: TMA (trimethylaluminum) is carried into the chemical vapor deposition chamber by high-purity N2, so that TMA is saturated and adsorbed on the cut surface of the half-cell. The source tank temperature of TMA is 50 ℃, the flow rate of high-purity N2 carrying TMA is 5000 sccm, and the source time is 5 s. First purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 5s. S5.2 Introducing nitrous oxide and maintaining constant chamber pressure: Nitrous oxide is introduced into the chemical vapor deposition chamber, and the constant chamber reaction pressure is 120 Pa, wherein the flow rate of nitrous oxide is 5000 sccm, and the induction time is 5 s; Nitrous oxide ionization: Nitrous oxide is introduced into the chemical vapor deposition chamber for ionization treatment. The flow rate of nitrous oxide is 5000 sccm, the power supply time is 5 s, the radio frequency power supply is 40 kHz, the discharge power is 5500 W, the switching ratio is 5:50, and the reaction pressure is 120 Pa. Secondary purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 6 s. Repeat steps S5.1 and S5.2 100 times to deposit an aluminum oxide film with a thickness of 12 nm on the cut surface of the half-cell.

[0044] S6 Introducing ammonia and nitrous oxide, maintaining a constant chamber pressure: Ammonia and nitrous oxide are introduced into the chemical vapor deposition chamber, maintaining a constant chamber reaction pressure of 120 Pa, with a flow rate of 3000 sccm for ammonia and 2000 sccm for nitrous oxide, and a source induction time of 5 s. Ammonia and nitrous oxide are introduced for plasma treatment: Ammonia and nitrous oxide are introduced into the high chemical vapor deposition chamber for pre-ionization, wherein the flow rate of ammonia is 3000 sccm, the flow rate of nitrous oxide is 2000 sccm, the power supply time is 5 s, the radio frequency power supply is 40 kHz, the discharge power is 5000 W, the switching ratio is 5:50, and the reaction pressure is 120 Pa. Nitrogen purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 6 s. Vacuuming: The chemical vapor deposition chamber is evacuated to a vacuum level of 10 mTorr.

[0045] S7: The aluminum oxide film layer on the cut surface of the half-cell solar cell is heated and irradiated with an infrared lamp to perform annealing treatment. The annealing temperature is 330 ℃ and the annealing time is 30 min. After the annealing treatment, the chemical vapor deposition chamber is filled with N2 to atmospheric pressure, and the carrier exits the chamber to obtain an edge-passivated solar half-cell solar cell.

[0046] Comparative Example 3 A method for passivating the edge of a solar cell half-cell includes the following steps: S1 provides a chemical vapor deposition chamber, which includes upper and lower electrode plates and a carrier conveying device. The conveying device has several carriers that can hold half-cell solar cells. The carriers are provided with openings for the deposition film, and infrared lamp heating devices are located in the direction of the deposition film openings. The LECO (laser-assisted sintering) solar cells are cut in half, and the cut halves are stacked neatly in the carriers so that the cut surfaces of the half-cells are on the same plane (e.g., ...). Figure 1 As shown), the cut surface of half of the battery cell is fully exposed at the opening of the substrate deposition film layer, and the cut surface is parallel to the airflow direction in the cavity. The substrate is then transported to the chemical vapor deposition chamber by a conveying device.

[0047] S2 evacuates the cavity to a vacuum level of 10 mTorr and heats it to 150 °C to perform vacuum preheating treatment on half of the solar cell for 30 min.

[0048] S3 deposits the first alumina film layer, specifically: S3.1 Introducing TMA: TMA (trimethylaluminum) is carried into the chemical vapor deposition chamber by high-purity N2, so that TMA is saturated and adsorbed on the cut surface of the half-cell. The source tank temperature of TMA is 50 ℃, the flow rate of high-purity N2 carrying TMA is 5000 sccm, and the source time is 5 s. First purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 5 s. S3.2 Introducing water vapor: Water vapor (oxygen source) is carried into the chemical vapor deposition chamber by high-purity N2, so that the water vapor reacts with TMA adsorbed on the cut surface of the half-cell to form an alumina layer. The temperature of the water vapor source tank is 30 ℃, the flow rate of high-purity N2 carrying the oxygen source water vapor is 3000 sccm, and the introducing time is 5 s. Secondary purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 6 s. Repeat steps S3.1 and S3.2 50 times to deposit an aluminum oxide film with a thickness of 12 nm on the cut surface of the half-cell. S4 deposits the second alumina film layer, specifically as follows: S4.1 Introducing TMA: TMA (trimethylaluminum) is carried into the chemical vapor deposition chamber by high-purity N2, so that TMA is saturated and adsorbed on the cut surface of the half-cell. The temperature of the TMA source tank is 50 ℃, the flow rate of high-purity N2 carrying TMA is 5000 sccm, and the introducing time is 5 s. First purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 5 s. S4.2 Introducing nitrous oxide and maintaining constant chamber pressure: Nitrous oxide is introduced into the chemical vapor deposition chamber, and the constant chamber reaction pressure is 120 Pa, wherein the flow rate of nitrous oxide is 5000 sccm, and the induction time is 5 s; Nitrous oxide ionization: Nitrous oxide is introduced into the chemical vapor deposition chamber for ionization treatment. The flow rate of nitrous oxide is 5000 sccm, the power supply time is 5 s, the radio frequency power supply is 40 kHz, the discharge power is 5500 W, the switching ratio is 5:50, and the reaction pressure is 120 Pa. Secondary purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 6 s. Repeat steps S4.1 and S4.2 50 times to deposit an aluminum oxide film with a thickness of 12 nm on the cut surface of the half-cell. S5 uses an infrared lamp to heat and irradiate the aluminum oxide film layer on the cut surface of the half-cell solar cell for annealing treatment. The annealing temperature is 330℃ and the annealing time is 30min. After the annealing treatment, the chemical vapor deposition chamber is filled with N2 to atmospheric pressure, and the carrier exits the chamber to obtain a solar half-cell solar cell with passivated edges.

[0049] Comparative Example 4 A method for passivating the edge of a solar cell half-cell includes the following steps: S1 provides a chemical vapor deposition chamber, which includes upper and lower electrode plates and a carrier conveying device. The conveying device has several carriers that can hold half-cell solar cells. The carriers are provided with openings for the deposition film, and infrared lamp heating devices are located in the direction of the deposition film openings. The LECO (laser-assisted sintering) solar cells are cut in half, and the cut halves are stacked neatly in the carriers so that the cut surfaces of the half-cells are on the same plane (e.g., ...). Figure 1 As shown), the cut surface of half of the battery cell is fully exposed at the opening of the substrate deposition film layer, and the cut surface is parallel to the airflow direction in the cavity. The substrate is then transported to the chemical vapor deposition chamber by a conveying device.

[0050] S2 evacuates the cavity to a vacuum level of 10 mTorr and heats it to 150 ℃ to perform vacuum preheating treatment on half of the solar cell for 30 min.

[0051] S3 Introducing ammonia and nitrous oxide, maintaining constant chamber pressure: Ammonia and nitrous oxide are introduced into the chemical vapor deposition chamber, maintaining a constant chamber reaction pressure of 120 Pa, with an ammonia flow rate of 3000 sccm and a nitrous oxide flow rate of 2000 sccm, and an induction time of 5 s; Ammonia and nitrous oxide were introduced for plasma pretreatment: Ammonia and nitrous oxide were introduced into the high chemical vapor deposition chamber for pre-ionization, wherein the flow rate of ammonia was 3000 sccm, the flow rate of nitrous oxide was 2000 sccm, the power supply time was 5 s, the radio frequency power supply used was 40 kHz, the discharge power was 5000 W, the switching ratio was 5:50, and the reaction pressure was 120 Pa. Nitrogen purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 6 s. Vacuuming: The chemical vapor deposition chamber is evacuated to a vacuum level of 10 mTorr.

[0052] S4 deposits an alumina film, specifically as follows: S4.1 Introducing TMA: TMA (trimethylaluminum) is carried into the chemical vapor deposition chamber by high-purity N2, so that TMA is saturated and adsorbed on the cut surface of the half-cell. The source tank temperature of TMA is 50 ℃, the flow rate of high-purity N2 carrying TMA is 5000 sccm, and the source time is 5 s. First purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 5 s. S4.2 Introducing water vapor: Water vapor (oxygen source) is carried into the chemical vapor deposition chamber by high-purity carrier gas N2, so that the water vapor reacts with TMA adsorbed on the cut surface of the half-cell to form an alumina layer. The temperature of the water vapor source tank is 30°C, the flow rate of high-purity N2 carrying the oxygen source water vapor is 3000 sccm, and the introducing time is 5 s. Secondary purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 6 s. Repeat steps S4.1 and S4.2 100 times to deposit an aluminum oxide film with a thickness of 12 nm on the cut surface of the half-cell. S5 Introducing ammonia and nitrous oxide, maintaining constant chamber pressure: Ammonia and nitrous oxide are introduced into the chemical vapor deposition chamber, maintaining a constant chamber reaction pressure of 120 Pa, with an ammonia flow rate of 3000 sccm and a nitrous oxide flow rate of 2000 sccm, and an induction time of 5 s; Ammonia and nitrous oxide are introduced for plasma treatment: Ammonia and nitrous oxide are introduced into the high chemical vapor deposition chamber for pre-ionization, wherein the flow rate of ammonia is 3000 sccm, the flow rate of nitrous oxide is 2000 sccm, the power supply time is 5 s, the radio frequency power supply is 40 kHz, the discharge power is 5000 W, the switching ratio is 5:50, and the reaction pressure is 120 Pa. Nitrogen purging: High-purity N2 is introduced into the chemical vapor deposition chamber for purging to remove unreacted gases or byproducts of the reaction. The flow rate of the purging N2 is 15000 sccm and the purging time is 6 s. Vacuuming: The chemical vapor deposition chamber is evacuated to a vacuum level of 10 mTorr.

[0053] S6 uses an infrared lamp to heat and irradiate the aluminum oxide film layer on the cut surface of the half-cell solar cell for annealing treatment. The annealing temperature is 330 ℃ and the annealing time is 30 min. After the annealing treatment, the chemical vapor deposition chamber is filled with N2 to atmospheric pressure, and the carrier exits the chamber to obtain an edge-passivated solar half-cell solar cell.

[0054] Test case Because the cut surface of a half-cell solar cell is narrow, it is impossible to directly measure the thickness of its alumina film. Therefore, the alumina film thickness of the cut surface of the corresponding embodiment or comparative example is measured using polished wafers of the same batch as those of this invention after alkaline polishing. Specifically, the polished surface of the wafer is placed in the chamber with the polished surface facing up (to passivate the polished surface). The passivation treatment is performed according to the methods of Examples 1-3 or Comparative Examples 2-4. Then, the uniformity of the alumina film thickness of the wafer is detected by a full-spectrum ellipsometry. The test positions are the four corners and the center of the wafer. Points 1-4 represent the four corners of the wafer, and the center represents the center of the wafer. The uniformity of the alumina film is calculated, and the test results are shown in Table 1 below.

[0055] Table 1

[0056] The edge-passivated half-cell solar cells obtained in Examples 1-3 and Comparative Examples 1-4 were encapsulated into modules. Performance tests were then conducted on the encapsulated photovoltaic modules. The photovoltaic module conversion efficiency (Voc, Isc, FF) was tested at a solar irradiance of 1000 W / m². 2 The surface temperature of the photovoltaic module reached 25 ℃±1 ℃, and the test results are shown in Table 2 below.

[0057] Table 2

[0058] In Table 2, Voc is the open-circuit voltage of the solar cell, Isc is the short-circuit current of the solar cell, FF is the fill factor of the solar cell, and Pmax is the power generation of the half-cell module after encapsulation.

[0059] The half-cell solar cells with edge passivation obtained in Examples 1-3 and Comparative Examples 2-4 were subjected to passivation testing using a WCT-120 minority carrier lifetime tester and quasi-steady-state photoconductivity (QSSPC) measurement method and analysis technique. The test results are shown in Table 3 below.

[0060] Table 3

[0061] In Table 3, iVoc refers to the open-circuit voltage.

[0062] As shown in Tables 1, 2, and 3, according to Embodiments 1-3 and Comparative Example 2 of the technical solutions in this application, with the increase of alumina film thickness and a relatively small increase in module power gain, the proportion of poor solder joints shows a significant increasing trend. Furthermore, when the total alumina film thickness reaches 24 nm and the first alumina film thickness reaches 12 nm, the proportion of poor solder joints increases substantially. This is because the plating range is larger, and after the edge passivation of the half-cell, the plating is closer to the pad points (electrode contact points) of the screen-printed metal grid lines, affecting module welding and thus leading to a significant increase in the proportion of poor solder joints. According to Embodiments 1 and Comparative Example 3 of the technical solutions in this application, this application performs plasma treatment on the cut surfaces of the laser-cut cells before alumina film deposition. While maintaining a similar alumina film thickness, it achieves superior alumina film uniformity. The cut surfaces of the half-cell adsorb more OH and H bonds with stronger binding energy. The increase in these two chemical bonds enhances field-effect passivation and hydrogen passivation, improving the passivation effect and thus obtaining higher module power. According to Embodiment 1 and Comparative Example 4 of the technical solution in this application, this application optimizes the process of half-wafer edge passivation deposition of alumina. By depositing two layers of alumina film, the chemical passivation effect of the alumina film is guaranteed without affecting the thickness and uniformity of the alumina film, and the range of plating is reduced, thereby reducing the proportion of cold solder joints in the component welding process.

[0063] After laser cutting, solar cells are prone to attracting dust and particulate matter from the air and the cutting process. This application addresses this issue by subjecting the laser-cut surface of the solar cell and the deposited alumina film to plasma treatment. Through plasma ionization and electric field acceleration, the cut surface of the half-cell is bombarded and cleaned, resulting in superior uniformity of the alumina film. Simultaneously, the cut surface of the half-cell exhibits increased adsorption of stronger OH and H bonds. This increase in these chemical bonds enhances field-effect passivation and hydrogen passivation, improving the passivation effect. The process of half-cell edge passivation deposition of alumina involves depositing two layers of alumina film. The first layer of alumina film reacts with TMA and water vapor, causing the adsorption of H bonds and providing excellent hydrogen passivation. Since water vapor is more likely to adhere to the gaps between cells and grid lines and is more difficult to clean, it is the main cause of winding plating. Therefore, the second layer of alumina film reacts with TMA and nitrous oxide. This process does not affect the thickness and uniformity of the alumina film while ensuring the chemical passivation effect of the alumina film, reducing the winding plating range, and thus reducing the proportion of poor solder joints during the module welding process.

[0064] The above description is merely a preferred embodiment of the present invention, and the present invention is not limited to the above embodiments. It is understood that other improvements and variations that are directly derived or conceived by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included within the protection scope of the present invention.

Claims

1. A method for passivating the edge of a solar cell half-cell, characterized in that, The method includes the following steps: S1 The battery cell is cut into half-cells, stacked so that the cut surfaces of the half-cells are on the same plane, and placed in the cavity of the chemical vapor deposition equipment; the cut surfaces are parallel to the airflow direction set in the cavity; S2 Evacuate the cavity and heat it to the preset reaction temperature to perform vacuum preheating treatment on the battery cells; S3 Ammonia and nitrous oxide are introduced to purge the cut surface of half of the battery cell for ionization pretreatment, followed by nitrogen blowing and vacuuming. S4 deposits the first aluminum oxide film layer, specifically as follows: S4.1 Introduce a carrier gas carrying TMA molecules to saturate the TMA with the cut surface of the half-cell, followed by nitrogen blowing. S4.2 Then, a carrier gas carrying water vapor is introduced, so that the water vapor reacts with TMA to form alumina, followed by a second nitrogen purging; Repeat steps S4.1 and S4.2 50 to 80 times to form the first layer of alumina film. S5 deposits the second alumina film layer, specifically as follows: S5.1 Introduce a carrier gas carrying TMA molecules to saturate the TMA with the cut surface of the half-cell, followed by nitrogen blowing. S5.2 Ionization treatment with nitrous oxide followed by secondary nitrogen blowing; Repeat steps S5.1 and S5.2 50 to 80 times to form the second aluminum oxide film layer; S6 Introduces ammonia and nitrous oxide to purge the cut surface of the half-cell for ionization pretreatment, followed by nitrogen blowing, vacuuming, and then annealing to obtain a solar half-cell with passivated edges.

2. The method according to claim 1, characterized in that, In step S1, the half-cell is transported to the cavity of the chemical vapor deposition equipment via a carrier, with the cut surface of the half-cell exposed and the other surfaces not exposed. Step S1 further includes: placing a flow equalization component near the air inlet, wherein the flow equalization component has multiple parallel airflow channels inside, and the axis of the airflow channels is parallel to the cut surface of the half-cell battery cell.

3. The method according to claim 1, characterized in that, In step S2, the temperature of the vacuum preheating treatment is 100-200 ℃, the vacuum degree is 10-30 mTorr, and the time is 30-60 min.

4. The method according to claim 1, characterized in that, In step S3, the flow rate of ammonia is 2000-5000 sccn, the flow rate of nitrous oxide is 1000-3000 sccm, and the on / off ratio is 3-5:50; the purging time is 5-10 s, and the reaction pressure is 100-180 Pa; the radio frequency power supply for the ionization pretreatment is 30-50 kHz, and the discharge power is 3000-8000 W; the flow rate of nitrogen purging is 10000-20000 sccm, and the time is 6-10 s; the vacuum degree is 10-30 mTorr.

5. The method according to claim 1, characterized in that, In step S4.1, the carrier gas is N2; the source tank temperature of the TMA is 50-60 ℃; the flow rate of the carrier gas carrying TMA molecules is 3000-8000 sccm, and the introduction time is 2-8 s; the flow rate of the nitrogen blowing is 10000-20000 sccm, and the time is 5-10 s. In step S4.2, the carrier gas is N2, the source tank temperature of the water vapor is 30-40 ℃, the flow rate of the carrier gas carrying the water vapor is 3000-5000 sccm, and the introduction time is 4-8 s; the flow rate of the secondary nitrogen blowing is 10000-20000 sccm, and the time is 6-10 s.

6. The method according to claim 1, characterized in that, In step S4, the thickness of the first alumina film layer is 6~10 nm.

7. The method according to claim 1, characterized in that, In step S5.1, the carrier gas is N2, the source tank temperature of the TMA is 50-60 ℃, the flow rate of the carrier gas carrying TMA molecules is 3000-8000 sccm, and the introduction time is 2-8 s; the flow rate of the nitrogen blowing is 10000-20000 sccm, and the time is 5-10 s; the flow rate of the secondary nitrogen blowing is 10000-20000 sccm, and the time is 6-10 s. In step S5.2, the flow rate of the nitrous oxide is 3000-6000 sccm, and the on / off ratio is 3-5:50; the radio frequency power supply for the ionization treatment is 30-50 kHz, the discharge power is 3000-8000 W, the time is 5-10 s, and the reaction pressure is 100-180 Pa; the flow rate of the secondary nitrogen blowing is 10000-20000 sccm, and the time is 6-10 s.

8. The method according to claim 1, characterized in that, In step S5, the thickness of the second alumina film layer is 6~10 nm.

9. The method according to claim 1, characterized in that, In step S6, the flow rate of ammonia is 2000-4000 sccm, the flow rate of nitrous oxide is 1000-3000 sccm, and the on / off ratio is 3-5:50; the purging time is 5-10 s, and the reaction pressure is 100-180 Pa; the radio frequency power supply for the ionization pretreatment is 30-50 kHz, and the discharge power is 3000-8000 W; the nitrogen blowing flow rate is 10000-20000 sccm, and the time is 6-10 s; the vacuum degree is 10-30 mTorr.

10. The method according to claim 1, characterized in that, In step S6, the annealing temperature is 280-400 ℃ and the time is 20-40 min.

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