Solar battery half-piece cutting surface repairing method, half-piece battery piece, battery pack and preparation method of battery pack

Abstract

The invention relates to a half-piece cutting and repairing method for a solar cell piece, a half-piece cell piece, a solar cell module and a preparation method of the solar cell module. According to the method, after the whole piece is cut through laser, the cutting face is sequentially subjected to alkali polishing treatment, laser energy oxidation and deposition passivation dual repair; wherein the surface of the alkali-polished plane is subjected to hydroxyl (-OH) treatment, so that the adsorption capacity of oxygen molecules can be improved, then laser energy acts on the oxygen molecules adsorbed on the cutting surface, silicon oxide is formed through oxidation, a silicon nitride layer is formed through deposition and passivation, and the cut solar cell half-piece section is obtained. The defects of microcracks and lattice damage of the cell cutting surface caused by laser cutting are repaired, and the power of the solar cell half-piece assembly is further improved.

Description

Technical Field

[0001] The present invention relates to the field of solar cells, and in particular to a method for repairing a half-cut surface of a solar cell, a half-cell cell, a battery pack and a preparation method thereof. Background Art

[0002] Driven by global energy transition goals, the photovoltaic industry's demand for high-power modules continues to climb. Compared to conventional full-cell modules, half-cell technology significantly reduces series resistance and improves fill factor (FF) by optimizing the cell layout, resulting in multiple advantages in power generation efficiency, levelized cost of electricity (LCOE), and system economics. This technology approach not only reduces costs for mounting systems and land by increasing per-watt output efficiency, but also reduces power generation losses caused by shading and dust and snow accumulation. Combined with its high maturity in large-scale mass production and manageable additional costs, it has become a core solution for replacing traditional energy sources.

[0003] The current mainstream half-cell module process uses laser cutting of whole cells to form symmetrical halves. While this process improves power output through parallel / series connection combined with bypass diodes, it faces inherent technical bottlenecks. Damage to the cell sides caused by the cutting process reduces conversion efficiency, offsetting some of the gains from the half-cell structure and limiting the power increase. Furthermore, the existing process requires secondary processing of the sorted, intact cells. Cutting defects can introduce the risk of hidden cracks, impacting the long-term reliability of the module and further limiting the performance optimization potential of half-cell technology.

[0004] The industry urgently needs to maintain the advantages of half-cell technology while overcoming the negative impact of existing processes on cell efficiency. The core conflict lies in the fact that while laser cutting simplifies the production process, physical damage and cell efficiency loss create a technical backlash. How to maximize conversion efficiency while achieving cell slicing through process innovation or structural optimization, thereby increasing the power gain of half-cell modules, remains a pressing technical challenge in this field. Summary of the Invention

[0005] The present invention is aimed at the above problems, makes up for the deficiencies of the prior art, and provides a method for repairing the cut surface of a half-cell solar cell, a half-cell cell, a battery pack and a preparation method thereof, so as to solve the problems arising from the above background technology.

[0006] The first aspect of the present invention provides a method for repairing the cut surface of a half-cell solar cell, comprising the following steps: using an alkali polishing technique to form a polishing plane containing -OH on the cut surface of the half-cell solar cell; forming an oxide layer on the polishing plane by a laser oxidation technique; and then depositing a silicon nitride layer on the oxide layer by a deposition passivation technique.

[0007] Preferably, the alkali polishing technology specifically uses a KOH solution or a NaOH solution as the alkali solution, the percentage concentration of the alkali solution is 10~30%, the polishing temperature is 50~70℃, the polishing time is 100~200s, the reflectivity of the plane after the alkali polishing treatment is 35~45%, and the surface roughness Ra is 0.5~1μm.

[0008] Preferably, the laser oxidation technology is specifically to scan the polishing surface formed by the alkali polishing technology in an environment with an oxygen purity of 5N or above and a flow rate of 1000~3000sccm, using a laser with a power of 100~200W, a scanning speed of 0.1~10m / s, a spot size of 10-50μm, and a scanning time of 2~10s.

[0009] Preferably, the deposition passivation technology adopts CVD technology, and the deposition gases used in the CVD technology are silane and ammonia, the silane flow rate is 1-3slm, the ammonia flow rate is 3-9slm, the deposition temperature is 150~600℃, the deposition pressure is 150~600Pa, and the deposition time is 5~20min.

[0010] Preferably, the plane reflectivity after the alkali polishing treatment is 35-45%, and the surface roughness Ra is 0.5-1 μm.

[0011] The present invention also provides a half-cell solar cell, which includes a half-cell cell cut by laser, a polished plane formed on the cut surface using the above-mentioned cutting surface repair method, an oxide layer formed on the polished plane, and a silicon nitride layer formed on the oxide layer.

[0012] Preferably, the oxide layer is a silicon dioxide layer with a thickness of 5 to 15 nm and a refractive index of 1.4 to 1.8.

[0013] Preferably, the silicon nitride layer has a thickness of 10-30 nm and a refractive index of 2.0-2.8.

[0014] Preferably, the battery cell is a BC battery, a TOPCon battery, a perc battery or a HJT battery.

[0015] The present invention also provides a solar cell group, characterized in that it includes multiple solar half-cell cells as described above, wherein the solar half-cell cells are connected in series to form a half-cell cell string, and the half-cell cell strings are connected in parallel to form a solar cell group.

[0016] The present invention also provides a method for preparing a solar cell group, comprising the following steps:

[0017] 1) Perform performance tests on the entire solar cell and keep good solar cells;

[0018] (2) laser cutting the good solar cell to form multiple half-cell cells;

[0019] (3) repairing the cut surface of the half-cell, specifically, using an alkali polishing technique to form a polishing plane containing -OH on the cut surface of the half-cell solar cell, using a laser oxidation technique to form a silicon oxide layer on the polishing surface; and then depositing a silicon nitride layer on the oxide layer using a deposition passivation technique;

[0020] (4) Performing a performance test on the half-cell repaired in step (3), leaving the other half of the solar cell as good;

[0021] (5) The good half solar cell sheets are serially welded, packaged and laminated to form a solar cell module.

[0022] Preferably, the performance tests in step (1) and step (4) include battery efficiency, EL and PL tests to distinguish good cells from bad cells.

[0023] Preferably, the laser cutting is to cut the entire solar cell into n equal parts, where n is an integer greater than or equal to 2.

[0024] Preferably, the entire solar cell is in the shape of a rectangle, a circle or a square.

[0025] Preferably, the alkaline polishing liquid is KOH or NaOH, and the concentration of the alkaline solution is 5-20%.

[0026] Preferably, the laser spot used in the laser oxidation technology is a flat-top spot with a size of 10-50 μm.

[0027] Preferably, the laser power density used in the laser oxidation technology is 10 6 -10 8 W / cm², the scanning path is spiral or serpentine.

[0028] PL (Photoluminescence) testing involves irradiating photovoltaic materials with light of a specific wavelength. Electrons in the material absorb the photon energy and are excited to a high-energy state. When these excited electrons return to their ground state, they emit light of a specific wavelength. This emitted light is then used to analyze the material's properties. PL testing can provide a preliminary assessment of cell performance, detecting defects, impurities, and inhomogeneities in the material. It can also be used to assess crystal quality. High-quality crystals typically exhibit strong PL signals and specific luminescence characteristics.

[0029] EL (electroluminescence) testing involves applying a voltage across a photovoltaic cell, causing electrons and holes in the cell to recombine and emit light under the action of the electric field. EL testing can also be used to detect defects in photovoltaic cells, such as cracks and broken gates. It can also evaluate the performance and efficiency of the cell and study the carrier transport and recombination processes within the cell.

[0030] Cell efficiency testing refers to the ability to convert solar energy into electrical energy. It is calculated using the following formula: Cell efficiency = output power / cell area.

[0031] Output power is measured using an IV tester. An IV tester (current-voltage tester) is a precision instrument that applies voltage and measures the current, plotting an IV characteristic curve (current-voltage relationship). It's used to evaluate the electrical performance and stability of electronic devices. The "IV" in its name stands for current (I) and voltage (V). Its core functions include measuring key parameters such as open-circuit voltage (Voc), short-circuit current (Isc), and maximum power (Pmax).

[0032] Compared with the prior art, the present invention has the following technical effects:

[0033] The present invention adopts alkali polishing technology, laser oxidation repair technology and combines it with deposition passivation technology to sequentially form a polishing plane, an oxide layer and a silicon nitride layer on the cut surface of a half-cell battery, thereby passivating defects, microcracks and impurities on the cut surface, repairing the composite damage caused by cutting damage, thereby improving the conversion efficiency of the battery cell and ultimately increasing the power of the solar cell module; at the same time, the alkali polishing technology adopted by the present invention polishes and removes the cutting damage layer and microcracks, limits the plane reflectivity and roughness, and makes the cut surface smooth and flat after alkali polishing, which is conducive to the subsequent growth of the oxide layer.

[0034] The laser oxidation repair technology adopted in the present invention limits the parameters of the laser, so that the high-energy laser beam can be more accurately focused on the polished cut surface, generating instantaneous high temperature, ensuring the precise control and uniformity of the oxide layer thickness during continuous processing, and reducing the heat-affected zone to avoid damage to the surface layer other than the cut surface; and the laser acts in an oxygen atmosphere, and the photon energy breaks the diatomic bond of O2, generating atomic oxygen (O), ionic oxygen (O + , O -) and ozone (O3). These reactive oxygen species have significantly greater oxidizing power than ordinary oxygen. After polishing the cut surface, the smoother surface facilitates the formation of a more stable and uniform silicon oxide layer. The silicon oxide formed after oxygen atoms repair dangling silicon bonds after polishing, combined with post-treatments such as high-temperature rapid annealing (CVD deposition of silicon nitride), can further reduce surface micro-defects (such as thermal donors and stacking faults), improve lattice integrity and gettering capacity, and thus achieve defect repair and passivation of side cuts. DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solutions of the present invention in conjunction with specific embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0036] Example 1

[0037] This embodiment provides a solar cell half-cell, including a TOPCon cell half-cell cut by laser, a silicon oxide layer with a thickness of 5 nm and a refractive index of 1.4 stacked on the cut surface, and a silicon nitride layer with a thickness of 10 nm and a refractive index of 2.0 stacked on the silicon oxide layer.

[0038] The above-mentioned method for repairing the half-cut surface of a solar cell comprises the following steps:

[0039] 1) Take a qualified 182mm TOPCon whole cell and use laser to evenly cut it into two solar half cells;

[0040] 2) Using a 10% NaOH solution, immerse the cut surface of a solar cell half in the NaOH polishing solution. The polishing solution temperature is controlled at 50°C and the polishing time is 100s. A polished surface with a plane reflectivity of 35% and a surface roughness of 1μm is formed on the cut surface.

[0041] 3) A solar cell half polished in step 2) was placed in an environment with an oxygen purity of 6N and a flow rate of 1000 sccm. The polished surface was scanned with a laser at a controlled laser power of 100W, a scanning speed of 5m / s, a spot size of 30μm, and a scanning time of 2s. A silicon dioxide layer with a thickness of 5nm and a refractive index of 1.4 was formed on the polished surface.

[0042] 4) Placing the solar cell half treated in step 3) in a CVD passivation deposition apparatus, introducing a mixture of silane and ammonia gas into the apparatus at a flow rate of 1 slm of silane and 7 slm of ammonia, and depositing a 10 nm thick silicon nitride layer having a refractive index of 2.0 on the surface of the silicon dioxide layer at a deposition temperature of 150°C, a deposition pressure of 300 Pa, and a deposition time of 5 minutes, to produce a repaired half-cell.

[0043] This embodiment also provides a 66-panel solar cell array, the preparation method of which includes the following steps:

[0044] 1) Perform the above repair on multiple cells, and take out 132 repaired half-cell cells that have been sorted by efficiency, EL and PL;

[0045] 2) Divide into 6 groups, each with 22 cells connected in series, and then connect the groups in parallel to form a solar cell group.

[0046] This embodiment also provides a 72-piece solar cell array, the preparation method of which includes the following steps:

[0047] 1) Perform the above repair on multiple cells, and take out 144 repaired half-cells after efficiency, EL and PL sorting;

[0048] 2) Divide into 6 groups, each with 24 cells connected in series, and then connect the groups in parallel to form a solar cell group.

[0049] Example 2

[0050] This embodiment provides a solar cell half-cell, including a TOPCon cell half-cell cut by laser, a silicon oxide layer with a thickness of 15 nm and a refractive index of 1.8 stacked on the cut surface, and a silicon nitride layer with a thickness of 30 nm and a refractive index of 2.8 stacked on the silicon oxide layer.

[0051] The above-mentioned method for repairing the half-cut surface of a solar cell comprises the following steps:

[0052] 1) Take several pieces of qualified 182mm TOPCon whole cells and cut them into two solar half cells evenly using laser;

[0053] 2) Using a 30% NaOH solution, immerse the cut surfaces of multiple solar cell halves simultaneously in the NaOH polishing solution. The polishing solution temperature is controlled at 70°C and the polishing time is 200 seconds. A polished surface with a plane reflectivity of 45% and a surface roughness of 0.5 μm is formed on the cut surface.

[0054] 3) A solar cell half polished in step 2) was placed in an environment with an oxygen purity of 6N and a flow rate of 3000 sccm. The cut surface was scanned with a laser at a controlled laser power of 200W, a scanning speed of 5m / s, and a scanning time of 10s. A silicon oxide layer with a thickness of 15nm and a refractive index of 1.8 was formed on the polished surface.

[0055] 4) The stacked solar cell half-cells treated in step 3) are placed in a CVD passivation deposition apparatus. A mixture of silane and nitrogen is introduced into the apparatus, with a silane flow rate of 3 slm and an ammonia flow rate of 9 slm. A silicon nitride layer with a thickness of 30 nm and a refractive index of 2.8 is deposited on the surface of the silicon oxide layer at a deposition temperature of 600°C, a deposition pressure of 600 Pa, and a deposition time of 20 min to prepare a plurality of repaired half-cell cells.

[0056] This embodiment also provides a 66-panel solar cell array, the preparation method of which includes the following steps:

[0057] 1) Perform the above repair on multiple cells, and take out 132 repaired half-cell cells that have been sorted by efficiency, EL and PL;

[0058] 2) Divide into 6 groups, each with 22 cells connected in series, and then connect the groups in parallel to form a solar cell group.

[0059] This embodiment also provides a 72-piece solar cell array, the preparation method of which includes the following steps:

[0060] 1) Perform the above repair on multiple cells, and take out 144 repaired half-cells after efficiency, EL and PL sorting;

[0061] 2) Divide into 6 groups, each with 24 cells connected in series, and then connect the groups in parallel to form a solar cell group.

[0062] Example 3

[0063] This embodiment provides a solar cell half-cell, including three halves of a TOPCon cell cut by laser, a silicon oxide layer with a thickness of 10 nm and a refractive index of 1.6 stacked on the cut surface, and a silicon nitride layer with a thickness of 20 nm and a refractive index of 2.4 stacked on the silicon oxide layer.

[0064] The above-mentioned method for repairing the half-cut surface of a solar cell comprises the following steps:

[0065] 1) Take several pieces of qualified 210mm TOPCon whole cells and cut them into three solar half cells by laser;

[0066] 2) Using a 20% KOH solution, immerse the cut surfaces of multiple solar cell trisection panels simultaneously in the KOH polishing solution. The polishing solution temperature is controlled at 60°C and the polishing time is 150 seconds. A polished surface with a plane reflectivity of 40% and a surface roughness of 0.7 μm is formed on the cut surface.

[0067] 3) placing a solar cell polished in step 2) in an environment with an oxygen purity of 6N and an oxygen flow rate of 2000 sccm, and scanning the cut surface with a laser at a controlled laser power of 150 W, a scanning speed of 5 m / s, and a scanning time of 5 s to form a 10 nm thick silicon oxide layer on the cut surface;

[0068] 4) The stacked solar cell tri-slice layers treated in step 3) are placed in a CVD passivation deposition apparatus. A mixture of silane and nitrogen is introduced into the apparatus, with a silane flow rate of 2 slm and an ammonia flow rate of 3 slm. A silicon nitride layer with a thickness of 20 nm and a refractive index of 2.4 is deposited on the surface of the silicon oxide layer at a deposition temperature of 300°C, a deposition pressure of 300 Pa, and a deposition time of 12 min to prepare a repaired multi-slice tri-slice cell.

[0069] This embodiment also provides a 66-panel solar cell array, the preparation method of which includes the following steps:

[0070] 1) Perform the above repair on multiple cells, and take out 198 repaired three-and-a-half cells that have been sorted by efficiency, EL, and PL;

[0071] 2) Divide into 6 groups, each with 33 cells connected in series, and then connect the groups in parallel to form a solar cell group.

[0072] This embodiment also provides a 72-piece solar cell array, the preparation method of which includes the following steps:

[0073] 1) Perform the above repair on multiple cells, and take out 216 repaired 3 / 4 cells after efficiency, EL and PL sorting;

[0074] 2) Divide into 6 groups, each group has 36 cells connected in series, and then the groups are connected in parallel to form a solar cell group.

[0075] Example 4

[0076] This embodiment provides a half-cell solar cell, comprising three halves of an HJT cell cut by laser, with a silicon oxide layer having a thickness of 10 nm and a refractive index of 1.6 stacked on the cut surface, and a silicon nitride layer having a thickness of 20 nm and a refractive index of 2.4 stacked on the silicon oxide layer.

[0077] The above-mentioned method for repairing the half-cut surface of a solar cell comprises the following steps:

[0078] 1) Take several pieces of qualified 210mm HJT whole cell and cut them into three solar half cells by laser;

[0079] 2) Using a 20% KOH solution, immerse the cut surfaces of multiple solar cell trisection panels simultaneously in the KOH polishing solution. The polishing solution temperature is controlled at 60°C and the polishing time is 150 seconds. A polished surface with a plane reflectivity of 40% and a surface roughness of 0.7 μm is formed on the cut surface.

[0080] 3) placing a solar cell half polished in step 2) in an environment with an oxygen purity of 6N and an oxygen flow rate of 2000 sccm, and scanning the cut surface with a laser at a controlled laser power of 150 W, a scanning speed of 5 m / s, and a scanning time of 5 s to form a silicon oxide layer with a thickness of 10 nm on the cut surface;

[0081] 4) The stacked solar cell three-piece layers treated in step 3) are placed in a CVD passivation deposition apparatus. A mixture of silane and nitrogen is introduced into the apparatus, with a silane flow rate of 2 slm and an ammonia flow rate of 6 slm. A silicon nitride layer with a thickness of 20 nm and a refractive index of 2.4 is deposited on the surface of the silicon oxide layer at a deposition temperature of 300°C, a deposition pressure of 150 Pa, and a deposition time of 12 min to prepare a repaired multi-piece three-piece solar cell.

[0082] This embodiment also provides a 66-panel solar cell array, the preparation method of which includes the following steps:

[0083] 1) Perform the above repair on multiple cells, and take out 198 repaired three-and-a-half cells that have been sorted by efficiency, EL, and PL;

[0084] 2) Divide into 6 groups, each with 33 cells connected in series, and then connect the groups in parallel to form a solar cell group.

[0085] This embodiment also provides a 72-piece solar cell array, the preparation method of which includes the following steps:

[0086] 1) Perform the above repair on multiple cells, and take out 216 repaired 3 / 4 cells after efficiency, EL and PL sorting;

[0087] 2) Divide into 6 groups, each group has 36 cells connected in series, and then the groups are connected in parallel to form a solar cell group.

[0088] Comparative Example 1

[0089] This comparative example provides a half-cell solar cell, which is different from Example 1 in that the cut surface is not repaired.

[0090] Comparative Example 2

[0091] This comparative example provides a half-cell solar cell, which differs from Example 1 in that a different repair method is used, specifically: the solar half-cell is placed in an alumina deposition device, and a layer of alumina film with a thickness of 28 mm is coated on the cut surface.

[0092] Comparative Example 3

[0093] This comparative example provides a half-cell solar cell, which differs from Example 1 in that a different repair method is used, specifically: a mixed slurry of hydrogen peroxide and silicon dioxide is coated on the cut surface of the solar half-cell, and then a 28mm silicon oxide passivation layer is formed under ultraviolet light.

[0094] Comparative Example 4

[0095] This comparative example provides a solar cell half-cell, which differs from Example 1 in that a different repair method is used, specifically: a 28nm silicon nitride passivation layer is deposited only on the cut surface of the solar cell half-cell.

[0096] Comparative Example 5

[0097] This comparative example provides a half-cell solar cell, which is different from Example 3 in that the cut surface is not repaired.

[0098] Comparative Example 6

[0099] This comparative example provides a half-cell solar cell, which is different from Example 4 in that the cut surface is not repaired.

[0100] Comparative Examples 1-4 used the same method as Examples 1-2 to prepare a 66-panel solar cell array and a 72-panel solar cell array. Comparative Example 5 used the same method as Example 3 to prepare a 66-panel solar cell array and a 72-panel solar cell array. Comparative Example 6 used the same method as Example 4 to prepare a 66-panel solar cell array and a 72-panel solar cell array.

[0101] Performance tests were conducted on the repaired cell halves from Examples 1-4 and Comparative Examples 1-6, solar cell arrays, and cell halves from the comparative examples. The primary test parameter for the cell halves was the photoelectric conversion efficiency (η); the primary test parameter for the solar cell array was its maximum power (Pmax).

[0102] The test environment is controlled at 24±1°C using a cooling controller, and comprehensive electrical performance is measured using a solar simulator or IV tester. The light intensity of the light source used in the solar simulator or IV tester must be calibrated using a "standard cell" (standard performance cell).

[0103] The specific test results are shown in Table 1.

[0104] Table 1

[0105]

[0106] As shown in Table 1, Examples 1 and 2 both use 66×2 and 72×2 half-cell modules, prepared by cutting TOPCon 182mm full-sheet cells into half-cell structures. By depositing the laminated passivation structure provided by this application on the cut surfaces, the module power is significantly higher than that of Comparative Example 1, and the cell conversion efficiency is significantly improved. Due to the advantages of the laminated passivation structure of the present invention, the module power is slightly higher than the single-layer passivation structures of Comparative Examples 2-3-4, and the cell conversion efficiency is also improved.

[0107] Example 3 is a 66×3 and 72×3 three-piece module prepared by cutting the TOPCon 210mm whole cell into three- and half-piece structures. The stacked passivation structure provided in this application is deposited on the cut surface. Because it is divided into three pieces, the single whole-piece passivation repairs 4 sides, which is twice the 2 sides of the half-piece passivation. Therefore, the power improvement of the module is significantly higher than that of Comparative Example 5, and the battery conversion efficiency is also significantly improved.

[0108] Example 4 is a 66×3 and 72×3 three-piece component prepared by cutting the HJT 210mm whole cell into three-piece and half-piece structures. The stacked passivation structure provided in this application is deposited on the cut surface. Because it is divided into 3 pieces, the single whole-piece passivation repairs 4 sides, which is twice the 2 sides of the half-piece passivation. Therefore, the component power improvement is significantly higher than that of Comparative Example 6, and the battery conversion efficiency is also significantly improved.

[0109] The present invention is further described above with the aid of specific embodiments. However, it should be understood that the specific description herein should not be construed as limiting the essence and scope of the present invention. Various modifications made to the above embodiments by ordinary technicians in this field after reading this specification are all within the scope of protection of the present invention.

Claims

1. A method for repairing a half-cut surface of a solar cell, characterized in that: The method comprises the following steps: forming a polishing plane containing -OH on a cut surface of a half-cell solar cell by using an alkali polishing technique; forming an oxide layer on the polishing plane by using a laser oxidation technique; and then depositing a silicon nitride layer on the oxide layer by using a deposition passivation technique.

2. A method for repairing a half-cut surface of a solar cell according to claim 1, characterized in that: The alkali polishing technology specifically uses a KOH solution or a NaOH solution as the alkali solution, the alkali solution concentration is 10~30%, the polishing temperature is 50~70℃, and the polishing time is 100~200s; the plane reflectivity after the alkali polishing treatment is 35~45%, and the surface roughness Ra is 0.5~1μm.

3. A method for repairing a half-cut surface of a solar cell according to claim 1, characterized in that: The laser oxidation technology specifically involves scanning the polished surface in an environment with an oxygen purity of 5N or above and a flow rate of 1000-3000sccm, using a laser with a power of 100-200W, a scanning speed of 0.1-10m / s, a spot size of 10-50μm, and a scanning time of 2-10s.

4. A method for repairing a half-cut surface of a solar cell according to claim 1, characterized in that: The deposition passivation technology adopts CVD technology. The deposition gases used in the CVD technology are silane and ammonia. The silane flow rate is 1-3slm, the ammonia flow rate is 3-9slm, the deposition temperature is 150~600℃, the deposition pressure is 150~600Pa, and the deposition time is 5~20min.

5. A half-cell solar cell, characterized in that: The invention comprises a half-cell cell cut by laser, a method for repairing a cut surface of a solar cell half-cell as described in claims 1-4, a polished plane formed on the cut surface, an oxide layer formed on the polished plane, and a silicon nitride layer formed on the oxide layer.

6. The solar cell half-cell according to claim 5, characterized in that: The oxide layer is a silicon dioxide layer with a thickness of 5 to 15 nm and a refractive index of 1.4 to 1.8; the silicon nitride layer has a thickness of 10 to 30 nm and a refractive index of 2.0 to 2.

8.

7. The solar cell half-cell according to claim 5, characterized in that: The battery cell is a BC battery, a TOPCon battery, a perc battery or a HJT battery.

8. A solar cell group, characterized in that: The solar cell comprises a plurality of half-cell solar cells according to any one of claims 5 to 7, wherein the half-cell solar cells are connected in series to form a half-cell cell string, and the half-cell cell strings are connected in parallel to form a solar cell group.

9. A method for preparing a solar cell assembly according to claim 8, characterized in that: The following steps are involved: (1) Perform performance tests on the entire solar cell and keep good solar cells; (2) laser cutting the good solar cell to form multiple half-cell cells; (3) repairing the cut surface of the half-cell, specifically, using an alkali polishing technique to form a polishing plane containing -OH on the cut surface of the half-cell solar cell, using a laser oxidation technique to form a silicon oxide layer on the polishing surface; and then depositing a silicon nitride layer on the oxide layer using a deposition passivation technique; (4) Performing a performance test on the half-cell repaired in step (3), leaving the other half of the solar cell as good; (5) The good half solar cell sheets are serially welded, packaged and laminated to form a solar cell module.

10. The method for preparing a solar cell according to claim 9, wherein: The performance tests in step (1) and step (4) include cell efficiency, EL and PL tests to distinguish good cells from bad cells.

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