A method for manufacturing a battery piece, a battery piece and a photovoltaic module

Abstract

A preparation method of a battery piece, the battery piece and a photovoltaic module. The preparation method of the battery piece comprises the following steps: providing a whole battery piece, positioning at least one cutting line on the surface of the whole battery piece, preparing an isolation part on the surface of the whole battery piece on both sides close to the at least one cutting line, laser cutting the whole battery piece along the at least one cutting line to form at least two split battery pieces, stacking the at least two split battery pieces in the thickness direction of the split battery pieces to make the cutting surfaces of the split battery pieces stacked to form a section, and depositing a passivation layer on the section. By preparing the isolation part on the surface of the whole battery piece, the isolation part can seal the gap between the adjacent two battery pieces after the split battery pieces are stacked, and the isolation part is located close to the cutting surface in the direction perpendicular to the deposition direction of the passivation layer, thereby reducing the risk of the passivation material penetrating along the above-mentioned gap and depositing on the front surface and the back surface of the split battery piece, reducing the risk of the battery piece generating around plating, and improving the electrical performance of the battery piece.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaic, in particular to a preparation method of a cell piece, a cell piece and a photovoltaic module. BACKGROUND

[0002] The whole cell can be cut to form a plurality of split cells. In the passivation process of the split cell cutting surface, a plurality of split cells need to be stacked and the cutting surfaces of each split cell are formed to one side to form a whole cross section, and then the cross section is uniformly passivated to improve the passivation efficiency of the split cell. However, in the process of passivating the cross section, because a plurality of split cells are placed adjacent to each other, there is a gap between adjacent split cells, which causes the passivation process gas to be plated around the split cell through the gap, thereby affecting the performance of the cell piece. SUMMARY

[0003] The present application provides a preparation method of a cell piece, a cell piece and a photovoltaic module, which are used to solve the problem of plating around the cell piece.

[0004] The first aspect of the present application provides a preparation method of a cell piece, which at least includes the following steps:

[0005] providing a whole cell;

[0006] positioning at least one cutting line on the surface of the whole cell;

[0007] preparing an isolation part on the surface of the whole cell along the two sides close to at least one cutting line;

[0008] laser cutting the whole cell along at least one cutting line to form at least two split cells;

[0009] stacking at least two split cells along the thickness direction of the split cell to make the cutting surface of each split cell stacked to form a cross section, and depositing a passivation layer on the cross section.

[0010] By preparing isolation portions on both sides of the surface of the entire cell near at least one cut line, the isolation portions are located between two adjacent cells after multiple cells are stacked in subsequent steps. The isolation portions are located near the cut surface along the deposition direction perpendicular to the passivation layer, so that the isolation portions can be used to fill and seal the gap between two adjacent cells in the stack. During the subsequent deposition of the passivation layer, the isolation portions can prevent the passivation material from penetrating to the front and back of the cells, thereby reducing the risk of passivation material penetrating and depositing on the front and back of the cells along the gap between two adjacent cells in the stack. This reduces the risk of local short circuits or poor contact caused by passivation, improves the open circuit voltage and fill factor, and is beneficial to improving the electrical performance of the cells, increasing production yield and appearance inspection pass rate.

[0011] In this solution, along the direction perpendicular to the cutting surface, the distance L1 between the edge of the isolation part near the cutting surface and the cutting surface satisfies: L1≤1mm;

[0012] The material of the isolation part is silicone or acrylic.

[0013] In this design, along the direction perpendicular to the cutting surface, the ratio of the dimension L2 of the insulating portion to the dimension L3 of the segmented battery satisfies: 3.2 10 -5 ≤L2 / L3≤2.5 10 -3 .

[0014] In this scheme, the dimension L2 of the isolation part along the direction perpendicular to the cutting surface satisfies: 5um≤L2≤200um.

[0015] In this scheme, the dimension D of the isolation part along the thickness direction of the segmented battery satisfies: 1um≤D≤20um.

[0016] In this scheme, along the direction perpendicular to the cut surface, the plating dimension F satisfies: F≤1mm.

[0017] In this solution, the method for preparing the battery cell includes the following steps in the step of positioning at least one cutting line on the surface of the entire battery cell:

[0018] At least two of the cutting lines are positioned on the surface of the entire battery cell;

[0019] In the step of preparing insulating portions on both sides of the surface of the entire battery cell near at least one of the cutting lines, the method for preparing the battery cell includes the following steps:

[0020] The insulating portion is prepared at both edges of the entire battery cell along the direction of the cutting line.

[0021] In this scheme, during the laser cutting process, the grooving power W1 satisfies: 0.1W≤W1≤150W, the grooving frequency Q satisfies: 60kHz≤Q≤100kHz, the thermal cracking power W2 satisfies: 0.05W≤W2≤50W, and the cutting speed V satisfies: 500mm / s≤V≤800mm / s.

[0022] In this scheme, along the direction perpendicular to the cutting surface, the size H of the passivation layer satisfies: 30nm≤H≤65nm. During the deposition of the passivation layer, the deposition temperature T satisfies: 200℃≤T≤300℃, and the deposition time R satisfies: 2h≤R≤4h.

[0023] A second aspect of this application provides a battery cell, which is prepared based on the battery cell preparation method described above;

[0024] The battery cell can be a back contact battery or a tunnel oxide passivated contact battery, and the isolation portion is disposed on the front side of the battery cell.

[0025] A third aspect of this application provides a photovoltaic module, which includes the solar cells described above.

[0026] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0027] Figure 1 A flowchart illustrating a specific embodiment of the method for preparing the battery cell provided in this application;

[0028] Figure 2 This is a schematic diagram of the structure formed in a specific embodiment of the method for preparing the battery cell provided in this application, specifically during step S3.

[0029] Figure 3 This is a schematic diagram of the structure formed in a specific embodiment of the method for preparing the battery cell provided in this application, specifically during step S4.

[0030] Figure 4 A schematic diagram from another perspective of the structure formed in step S4 of the method for preparing the battery cell provided in this application in one specific embodiment;

[0031] Figure 5 This is a schematic diagram of the structure formed in a specific embodiment of the method for preparing the battery cell provided in this application, specifically through step S5.

[0032] Figure 6This is a schematic diagram of the structure formed in a specific embodiment of the method for preparing the battery cell provided in this application, specifically through step S5.

[0033] Figure 7 This is a schematic diagram of the structure formed in another specific embodiment of the method for preparing the battery cell provided in this application by performing step S5;

[0034] Figure 8 This is a schematic diagram of the structure formed in another specific embodiment of the method for preparing the battery cell provided in this application, specifically step S3.

[0035] Figure 9 A schematic diagram of the structure formed in another specific embodiment of the method for preparing the battery cell provided in this application by performing step S3;

[0036] Figure 10 This is a circuit diagram of a photovoltaic module provided in this application in a specific embodiment;

[0037] Figure 11 This is a circuit diagram of a photovoltaic module provided in this application in one specific embodiment.

[0038] Explanation of reference numerals in the attached figures:

[0039] 1- The entire battery cell;

[0040] 11-Cutting line;

[0041] 2-Segmented battery;

[0042] 21-cut surface;

[0043] 3-section;

[0044] 4-Passivation layer;

[0045] 5-Isolation Department;

[0046] 6- Photovoltaic modules;

[0047] 61-Intermediate busbar;

[0048] 611 - First contact;

[0049] 612 - Second contact;

[0050] 613 - Third contact;

[0051] 614 - Fourth contact point;

[0052] 615 - Fifth contact point;

[0053] 62-First jumper busbar;

[0054] 63 - Second jumper busbar;

[0055] 641 - First battery string group;

[0056] 642 - Second battery string;

[0057] 643 - Third battery string;

[0058] 644 - Fourth battery string;

[0059] 645 - Fifth battery string;

[0060] 646 - Sixth battery string;

[0061] 65 - First diode;

[0062] 66 - Second diode;

[0063] 67 - Third diode.

[0064] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Detailed Implementation

[0065] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0066] In one specific embodiment, the present application will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0067] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0068] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0069] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0070] It should be noted that the directional terms such as "upper," "lower," "left," and "right" described in the embodiments of this application are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should be understood that when it is mentioned that an element is connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected to the other element "upper" or "lower" through an intermediate element.

[0071] This application provides a method for preparing a battery cell, such as... Figures 1-3 , Figure 5 and Figure 6 As shown, the method for preparing solar cells includes at least the following steps:

[0072] S1: Provides a complete battery cell 1;

[0073] S2: As Figure 2 As shown, at least one cutting line 11 is positioned on the surface of the entire battery 1;

[0074] S3: As Figure 2 As shown, an isolation portion 5 is prepared on both sides of the surface of the entire battery 1 near at least one cutting line 11;

[0075] S4: Laser cut the entire cell 1 along at least one cutting line 11 to form at least two segmented cells 2;

[0076] S5: At least two cell wafers 2 are stacked along the thickness direction of the cell wafers 2, so that the cut surfaces 21 of each cell wafer 2 are stacked to form a cross-section 3, and a passivation layer 4 is deposited on the cross-section 3. The passivation layer 4 can be an aluminum oxide thin film or a silicon nitride thin film. Depositing the passivation layer 4 on the cross-section 3 formed on the cut surface 21 is to repair the damage to the cut surface 21 caused by laser cutting in step S4. Depositing the passivation layer 4 on the cut surface 21 can effectively suppress carrier recombination.

[0077] Specifically, the isolation portion 5 can be disposed on the front side of the entire battery cell 1. In step S3, the isolation portion 5 is prepared on both sides of the surface of the entire battery cell 1 near at least one cutting line 11, so that in the subsequent step S5, after multiple battery cells 2 are stacked, the isolation portion 5 is located between two adjacent battery cells, and the isolation portion 5 is located near the cutting surface 21 along the deposition direction perpendicular to the passivation layer 4. This allows the isolation portion 5 to fill and seal the gap between two stacked adjacent battery cells. During the subsequent deposition of the passivation layer 4, the isolation portion 5 can prevent the passivation material from penetrating to the front and back sides of the battery cells 2, thereby reducing the risk of passivation material penetrating and depositing on the front and back sides of the battery cells 2 along the gap between two stacked adjacent battery cells. This reduces the risk of local short circuits or poor contact caused by passivation of the battery cells, improves the open circuit voltage and fill factor, and is beneficial to improve the electrical performance of the battery cells, increase production yield and appearance inspection pass rate.

[0078] It should be noted that "wrap-around plating" refers to the unexpected thin film deposition of the vapor phase precursor (the aforementioned passivation material) on silicon gaps or non-cut surfaces outside the target deposition area.

[0079] Furthermore, by performing step S3 before step S4, i.e., preparing the isolation portion 5 on the whole cell 1 before performing laser cutting, it is beneficial to avoid performing multiple individual processing operations on multiple cell pieces 2 cut from a whole cell 1. This reduces the number of operations required by the processing device to prepare the isolation portion 5 on the cell piece, which helps to improve the efficiency of the processing device in preparing the isolation portion 5 on the cell, speeds up the production cycle, and improves production efficiency. At the same time, the structural strength of the whole cell 1 is better than that of the cell pieces 2. When preparing the isolation portion 5 directly on the surface of the whole cell 1, the processing difficulty is reduced, which helps to reduce the risk of microcracks in the cell and further improves the production yield.

[0080] In this application, the material of the isolation part 5 is organosilicon or acrylic acid, that is, the isolation part 5 can be adhesive. Adhesive has a low cost, which helps to reduce the cost of producing battery cells.

[0081] Meanwhile, before step S4 is executed, the adhesive has been cured. The cured adhesive can be elastically deformed, that is, the isolation part 5 has elastic deformation capability. In step S5, the passivation clamping device is used to clamp the stacked multiple segmented batteries 2. The isolation part 5 undergoes elastic deformation under the pressure of the clamping device, so that the isolation part 5 can be tightly attached to the surface between two adjacent segmented batteries 2, improving the sealing effect of the isolation part 5, further reducing the risk of passivation material penetrating to the front and back of the segmented battery 2, thereby reducing the risk of plating around.

[0082] In one possible implementation, the method for preparing the battery cell further includes:

[0083] S6: Separate multiple cell segments 2 so that they are no longer stacked, so that they can be welded together to form a photovoltaic module 6.

[0084] Furthermore, it should be noted that the softening temperature of the cured adhesive is relatively high, typically above 300°C. The temperature of the process in step 5 is relatively low, which cannot reach the softening temperature of the adhesive, thus preventing the insulation part 5 from softening. This improves the reliability and stability of the insulation part 5 in sealing the gap between two adjacent stacked cell segments 2. At the same time, since the insulation part 5 is made of adhesive, there is no risk of softening, and there is no risk of the two adjacent stacked cell segments 2 sticking to each other through the insulation part 5. This reduces the operational difficulty of performing step S6 and helps to improve the production efficiency of the cell.

[0085] In one possible implementation, such as Figure 3 As shown, along the direction perpendicular to the cutting surface 21, the distance L1 between the edge of the isolation part 5 near the cutting surface 21 and the cutting surface 21 satisfies: L1≤1mm.

[0086] In this embodiment, when the value of L1 satisfies: L1≤1mm, in step 2, the isolation part 5 is controlled to be set at a distance ≤1mm from the cutting line 11 along the direction perpendicular to the cutting surface 21. This is done along the direction perpendicular to the cutting surface 21 so that the distance between the edge of the isolation part 5 near the cutting surface 21 and the cutting surface 21 is not too large, thereby reducing the risk that the passivation material will penetrate too much into the surface of the segmented battery 2 along the direction perpendicular to the cutting surface 21, and improving the effect of the isolation part 5 on the segmented battery 2 to produce a coating effect.

[0087] Optionally, L1 satisfies: L1≤1mm, and L1 can be 0mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1mm, or other values ​​within the above range. This embodiment does not impose any restrictions on this.

[0088] In one possible implementation, such as Figure 7 As shown, along the direction perpendicular to the cut surface 21, the plating dimension F satisfies: F ≤ 1 mm. F can be 0 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1 mm, or other values ​​within the above range. This embodiment does not impose any restrictions on this. For example, as... Figure 6 As shown, when L1 is 0mm, F can be 0mm, meaning that no plating is generated on the front and back of the segmented battery 2.

[0089] The "deposition size" refers to the size of the front and back sides of the cell 2, which are deposited outside the target deposition area, along the direction perpendicular to the cut surface 21, of the vapor phase precursor (the passivation material mentioned above).

[0090] In this embodiment, by satisfying L1≤1mm, the plating size F satisfies F≤1mm. Even if the surface of the segmented cell 2 is not plating or the plating size is small, the risk of local short circuit in the cell is reduced, the risk of carrier recombination is reduced, the fill factor and open circuit voltage are increased, the conversion efficiency of the cell is improved, and the pass rate of cell appearance inspection is improved.

[0091] In one possible implementation, such as Figure 3 As shown, the size of the isolation portion 5 is the same as the size of the segmented battery 2 along the direction parallel to the cutting surface 21, so that the isolation portion 5 can completely cover the segmented battery 2 along the direction parallel to the cutting surface 21, further improving the isolation portion 5 and reducing the risk of plating around the surface of the segmented battery 2 during passivation.

[0092] In one possible implementation, such as Figure 3 As shown, along the direction perpendicular to the cut surface 21, the ratio of the dimension L2 of the insulating part 5 to the dimension L3 of the segmented battery 2 satisfies: 3.2 10 -5 ≤L2 / L3≤2.5 10 -3 .

[0093] In this embodiment, the value of L2 / L3 satisfies: 3.2 10 -5 ≤L2 / L3≤2.5 10 -3 At the same time, the area occupied by the isolation part 5 on the surface of the cell 2 is moderate: the area occupied by the isolation part 5 on the surface of the cell 2 is not too large, which helps to reduce optical loss and improve the photoelectric conversion efficiency of the cell. At the same time, the area occupied by the isolation part 5 on the surface of the cell 2 is not too small, which improves the effect of the isolation part 5 in isolating the passivation material and further reduces the risk of plating around the surface of the cell.

[0094] Optionally, L2 / L3 satisfy 3.2 10 -5 ≤L2 / L3≤2.5 10 -3 The L2 / L3 ratio can be 3.2. 10 -5 3.5 10 -5 4 10 -5 4.5 10-5 4.7 10 -5 4.8 10 -5 5 10 -5 5.3 10 -5 5.5 10 -5 6 10 -5 7 10 -5 8 10 -5 9 10 -5 1 10 -4 5 10 -4 1 10 -3 1.8 10 -3 1.9 10 -3 2 10 -3 2.1 10 -3 2.2 10 -3 Or 2.5 10 -3 It can also be other values ​​within the above range, and this embodiment does not limit it.

[0095] In summary, the value of L1 satisfies: L1≤1mm, and the value of L2 / L3 satisfies: 3.2 10 -5 ≤L2 / L3≤2.5 10 -3 This allows the isolation portion 5 to be positioned closer to the edge of the cut surface 21 on the surface of the segmented cell 2, improving the reliability of mitigating the risk of plating around the cell and reducing the risk of optical loss caused by the isolation portion 5. Furthermore, after completing step S6, there is no need to add a step to remove the isolation portion 5, simplifying the process and improving production efficiency.

[0096] In one possible implementation, such as Figure 3 As shown, the dimension L2 of the isolation part 5 along the direction perpendicular to the cutting surface 21 satisfies: 5um≤L2≤200um.

[0097] In this embodiment, L2 satisfies: 5µm ≤ L2 ≤ 200µm. The size of the isolation portion 5 along the direction perpendicular to the cutting surface 21 is moderate: this ensures that the size L2 along the direction perpendicular to the cutting surface 21 is not too large, improving the light absorption efficiency of the solar cell and enhancing its aesthetics. Simultaneously, it ensures that the size L2 along the direction perpendicular to the cutting surface 21 is not too small, reducing the difficulty of fabricating the isolation portion 5 on the segmented solar cells 2, lowering production costs, and improving the reliability of the isolation portion 5 in sealing the gap between two adjacent segmented solar cells 2 in a stacked configuration.

[0098] Optionally, when the condition 5um≤L2≤200um is met, L2 can be 5um, 10um, 20um, 30um, 40um, 50um, 60um, 70um, 80um, 90um, 100um, 110um, 120um, 130um, 140um, 150um, 160um, 170um, 180um, 190um, or 200um, or other values ​​within the above range. This embodiment does not impose any restrictions on this.

[0099] In one possible implementation, such as Figure 4 As shown, the dimension D of the isolation part 5 along the thickness direction of the segmented battery 2 satisfies: 1um ≤ D ≤ 20um.

[0100] In this embodiment, when D satisfies 1µm ≤ D ≤ 20µm, the dimension D of the insulating portion 5 along the thickness direction of the segmented battery 2 is moderate. This ensures that the dimension of the insulating portion 5 along the thickness direction of the segmented battery 2 is not too large, reducing the risk of microcracks in the entire battery 1 caused by gravity during the fabrication of the insulating portion 5, reducing the fabrication difficulty of the insulating portion 5, and improving production efficiency. Simultaneously, ensuring that the dimension of the insulating portion 5 along the thickness direction of the segmented battery 2 is not too small improves the sealing effect between adjacent segmented batteries 2 in the sealed stack, reducing the risk of plating around the segmented batteries 2.

[0101] Optionally, when D satisfies: 1um≤D≤20um, D can be 1um, 2um, 3um, 4um, 5um, 6um, 7um, 8um, 9um, 10um, 11um, 12um, 13um, 14um, 15um, 16um, 17um, 18um, 19um or 20um, or other values ​​within the above range. This embodiment does not impose any restrictions on this.

[0102] The two cells of the battery provided in this application can be half-cell, three-cell, four-cell, or eight-cell cells, etc.

[0103] Specifically, such as Figure 2As shown, when it is necessary to prepare half-cells, step S2 is to locate a cutting line 11 on the surface of the whole cell 1, and step S4 is to perform laser cutting on the whole cell 1 along the cutting line 11 to form two half-cells. Since the cut surface 21 of the half-cell is only located on one side edge, each half-cell needs to be arranged so that the cut surfaces 21 of each half-cell are all facing one side and stacked, so that the cut surfaces 21 of all half-cells form a cross section 3, and a passivation layer 4 is deposited on the cross section 3.

[0104] In one possible implementation, such as Figure 8 and Figure 9 As shown, in the step of positioning at least one cutting line 11 on the surface of the entire battery cell 1, the method for preparing the battery cell includes the following steps:

[0105] At least two cutting lines 11 are positioned on the surface of the entire battery 1;

[0106] In the step of preparing the insulating portion 5 on both sides of the surface of the entire battery cell 1 near at least one cutting line 11, the battery cell preparation method includes the following steps:

[0107] Isolation portions 5 are prepared at both edges of the entire battery 1 along the direction of the cutting line 11.

[0108] Specifically, such as Figure 8 As shown, when a three-cell battery needs to be fabricated, step S2 involves positioning two cutting lines 11 on the surface of the entire battery 1. Step S3 involves fabricating isolation portions 5 on both sides of the surface of the entire battery 1 near the two cutting lines 11, and also fabricating isolation portions 5 at both edges of the entire battery 1 along the distribution direction of the cutting lines 11. Step S4 involves laser cutting the entire battery 1 along the two cutting lines 11 to form three three-cell batteries.

[0109] like Figure 9 As shown, when a quadruple battery needs to be fabricated, step S2 involves positioning three cutting lines 11 on the surface of the entire battery 1. Step S3 involves fabricating isolation portions 5 on both sides of the surface of the entire battery 1 near the three cutting lines 11, and also fabricating isolation portions 5 at the two edges of the entire battery 1 along the distribution direction of the cutting lines 11. Step S4 involves laser cutting the entire battery 1 along the three cutting lines 11 to form four quadruple batteries.

[0110] In this embodiment, such as Figure 8 and Figure 9As shown, when a whole cell 1 is laser-cut along at least two cutting lines 11, the partial cell 2 formed from multiple three-part cells, multiple four-part cells, or multiple eight-part cells of a whole cell 1 has two cutting surfaces 21. After stacking, two cross-sections 3 are formed, and passivation layers 4 need to be deposited on both cross-sections 3. Therefore, by preparing isolation portions 5 at both edges of the whole cell 1 along the direction of distribution of the cutting lines 11, so that isolation portions 5 are provided between each pair of adjacent cell 2 after stacking, the risk of plating around the edges of the cell 2 formed by cutting at the edge of the whole cell 1 is reduced during the deposition of passivation layer 4, thereby reducing the risk of plating around the surface of each cell 2 and improving the production quality of each cell 2.

[0111] In one possible implementation, such as Figure 1 As shown, during the laser cutting process, the grooving power W1 satisfies: 0.1W≤W1≤150W, the grooving frequency Q satisfies: 60kHz≤Q≤100kHz, the thermal cracking power W2 satisfies: 0.05W≤W2≤50W, and the cutting speed V satisfies: 500mm / s≤V≤800mm / s. This is beneficial for improving the cutting quality and enhancing the quality of the produced solar cells.

[0112] During the laser cutting process, grooving is performed first, followed by thermal cracking. Grooving refers to ablation of a guide groove or induced crack on the surface of the segmented battery 2 to provide a starting position for subsequent thermal cracking. Continuous laser is used for thermal cracking.

[0113] In this embodiment, when the grooving power W1 satisfies: 0.1W≤W1≤150W, and the grooving frequency Q satisfies: 60kHz≤Q≤100kHz, the values ​​of grooving power and grooving frequency are moderate, making the cut continuous and forming a complete guide groove, so that subsequent hot cracking treatment is easier, preventing the risk of carbonization and cracking of the battery cell, and helping to make the cut edge smooth and burr-free, thus improving the quality of the cut edge.

[0114] Optionally, the slotting power W1 satisfies: 0.1W≤W1≤150W. W1 can be 0.1W, 1W, 10W, 20W, 30W, 40W, 50W, 60W, 70W, 80W, 90W, 100W, 110W, 120W, 130W, 140W or 150W, or other values ​​within the above range. This embodiment does not impose any restrictions on this.

[0115] Optionally, the slotting frequency Q satisfies 60kHz≤Q≤100kHz. Q can be 60kHz, 65kHz, 70kHz, 75kHz, 80kHz, 85kHz, 90kHz, 95kHz or 100kHz, or other values ​​within the above range. This embodiment does not limit this.

[0116] When the thermal cracking power W2 satisfies the condition of 0.05W≤W2≤50W, the value of the thermal cracking power is moderate, which helps to make the cutting edge smooth and burr-free, prevents excessive thermal stress, reduces the risk of cracks deviating from the preset path and extending into the cell, and reduces the risk of microcracks in the cell, thus improving the production quality of the cell.

[0117] Optionally, the thermal cracking power W2 satisfies: 0.05W≤W2≤50W. W2 can be 0.05W, 1W, 5W, 10W, 15W, 20W, 25W, 30W, 35W, 40W, 45W or 50W, or other values ​​within the above range. This embodiment does not limit this.

[0118] When the cutting speed V satisfies: 500mm / s≤V≤800mm / s, the value of the cutting speed is moderate so that the entire battery 1 can be completely cut along the cutting line 11, improving the smoothness of the cutting edge and helping to improve cutting efficiency and increase the production yield of the segmented battery 2.

[0119] Optionally, the cutting speed V satisfies: 500mm / s≤V≤800mm / s. V can be 500mm / s, 550mm / s, 600mm / s, 650mm / s, 700mm / s, 750mm / s or 800mm / s, or other values ​​within the above range. This embodiment does not impose any restrictions on this.

[0120] In one possible implementation, such as Figure 6 As shown, along the direction perpendicular to the cutting surface 21, the size H of the passivation layer 4 satisfies: 30nm≤H≤65nm. During the deposition of the passivation layer 4, the deposition temperature T satisfies: 200℃≤T≤300℃, and the deposition time R satisfies: 2h≤R≤4h.

[0121] When H satisfies 30nm ≤ H ≤ 65nm, the dimension H of the passivation layer 4 in the direction perpendicular to the cut surface 21 is appropriately sized, ensuring that the dimension H of the passivation layer 4 in this direction is not too small. This prevents the passivation layer 4 from not completely covering the cross-section 3, increasing the charge density of the solar cell and thus improving the open-circuit voltage. Simultaneously, the dimension H of the passivation layer 4 in the direction perpendicular to the cut surface 21 is not too large, preventing excessive internal stress in the passivation layer 4, reducing the risk of cracking, and improving the quality of the passivation layer 4.

[0122] Optionally, H satisfies: 30nm≤H≤65nm. H can be 30nm, 35nm, 40nm, 45nm, 50nm, 55nm or 65nm, or other values ​​within the above range. This embodiment does not impose any restrictions on this.

[0123] When the deposition temperature T satisfies the condition 200℃≤T≤300℃, the value of the deposition temperature T is moderate: it prevents excessive thermal stress by ensuring the deposition temperature T is not too high, thus improving the film quality of the perovskite layer. Simultaneously, it prevents the deposition temperature T from being too low, providing the perovskite layer with density, preventing cracking, improving the passivation effect of the perovskite layer, and ultimately enhancing the film quality.

[0124] Optionally, when T satisfies 200℃≤T≤300℃, T can be 200℃, 210℃, 220℃, 230℃, 240℃, 250℃, 260℃, 270℃, 280℃, 290℃ or 300℃, or other values ​​within the above range. This embodiment does not impose any restrictions on this.

[0125] When the deposition time R satisfies 2h≤R≤4h, the size H of the deposited passivation layer 4 can be precisely controlled, which is beneficial to accelerate production efficiency and improve the film quality of the passivation layer 4.

[0126] Optionally, when R satisfies 2h≤R≤4h, R can be 2h, 2.5h, 3h, 3.5h or 4h, or other values ​​within the above range. This embodiment does not impose any restrictions on this.

[0127] This application also provides a battery cell, which is prepared by the battery cell preparation method in any of the above embodiments.

[0128] The solar cells can be back contact cells or tunnel oxide passivated contact cells.

[0129] The solar cell can be a back contact cell. For a back contact cell (BC), the emitter, surface field and metal electrode are all located on the back of the cell and are distributed in a cross-directional manner. The front of the cell uses a SiNx / SiOx double-layer anti-reflection passivation film, so that there is no metal electrode blocking the front of the cell, which allows the cell to receive more incident light, reduces optical loss and improves photoelectric conversion efficiency.

[0130] In other embodiments, the solar cell provided in this application can also be a tunnel oxide passivated contact (TOPCON) solar cell. The TOPCON solar cell, along its thickness direction, sequentially includes a silver electrode, a front surface silicon nitride passivation layer 4, a boron-doped emitter, an N-type substrate silicon layer, a diffusion doped layer, an ultrathin silicon oxide layer, doped polycrystalline silicon, silicon nitride, and a silver electrode. The back side of the cell consists of an ultrathin silicon oxide layer (1nm~2nm) and a phosphorus-doped microcrystalline amorphous mixed Si film, which together form a passivated contact structure, allowing the solder ribbon and busbar to also be disposed on the back side of the solar cell. This structure can block minority carrier hole recombination, increasing the open-circuit voltage and short-circuit current of the cell. The ultrathin oxide layer allows majority carrier electrons to tunnel into the polycrystalline silicon layer while blocking minority carrier hole recombination. The excellent passivation effect of ultrathin silicon oxide and heavily doped silicon films causes the energy bands on the silicon wafer surface to bend, thereby forming a field passivation effect. This significantly increases the probability of electron tunneling, reduces contact resistance, and improves the open-circuit voltage and short-circuit current of the battery, thus improving the battery conversion efficiency.

[0131] This application also provides a photovoltaic module 6, which includes the solar cells described in the above embodiments. The photovoltaic module 6 includes multiple solar cells and solder ribbons, which are used to connect the multiple solar cells in series to form a cell string.

[0132] When solar cells are used in photovoltaic module 6, the production yield and appearance inspection pass rate of solar cells with no or small winding plating are improved, and it is also beneficial to improve the open circuit voltage of photovoltaic module 6 and improve the photoelectric conversion efficiency of photovoltaic module 6.

[0133] When the solar cell is a back-contact cell, the back of the cell has both positive and negative electrodes, therefore, the solder ribbon is also located on the back of the back-contact cell. The insulating portion 5 is located on the front of the solar cell, that is, in step S2, the insulating portion 5 is located on the front of the entire solar cell 1. Since the solder ribbon and the insulating portion 5 are located on different surfaces of the solar cell, it can prevent the solder ribbon from pressing against the surface of the insulating portion 5 during the welding process, thereby preventing the risk of microcracks or fragmentation of the solar cell during welding and reducing the manufacturing difficulty of the photovoltaic module 6.

[0134] In addition, when performing current-voltage characteristic curve testing (IV testing) on ​​solar cells, the probe needs to contact the electrodes of the solar cell. Placing the isolation part 5 on the front side of the solar cell can prevent the isolation part 5 from affecting the test results and improve the accuracy of testing the performance of the solar cell.

[0135] The circuit of photovoltaic module 6 is as follows Figure 10 and Figure 11As shown, the photovoltaic module 6 also includes a central busbar 61, a first jumper busbar 62, a second jumper busbar 63, and multiple cell string groups. Three cell string groups are respectively arranged on the upper and lower sides of the central busbar 61. Each cell string group includes two cells connected in parallel. Each cell string includes multiple cells connected in series. Specifically, the cells located on the upper side of the central busbar 61, from left to right, are the first cell string group 641, the third cell string group 643, and the fifth cell string group 645; the cells located on the lower side of the central busbar 61, from left to right, are the second cell string group 642, the fourth cell string group 644, and the sixth cell string group 646. The two cell string groups located at the top and bottom (such as the first cell string group 641 and the second cell string group 642, the third cell string group 643 and the fourth cell string group 644, the fifth cell string group 645 and the sixth cell string group 646) are arranged symmetrically along the central busbar 61, including spatial symmetry and cell polarity symmetry. Two battery string groups located one above the other (such as the first battery string group 641 and the second battery string group 642, the third battery string group 643 and the fourth battery string group 644, the fifth battery string group 645 and the sixth battery string group 646) form a four-battery string parallel structure. The first battery string group 641, the third battery string group 643 and the fifth battery string group 645 are connected in series, and the second battery string group 642, the fourth battery string group 644 and the sixth battery string group 646 are connected in series.

[0136] One electrode of the first battery string group 641 and the second battery string group 642 is connected to the intermediate busbar 61 to form a first connection point. In this embodiment, this electrode can be the negative electrode, so that the photovoltaic module 6 is generally negative on the left and positive on the right. In other embodiments, this electrode can also be the positive electrode, so that the photovoltaic module 6 is generally negative on the right and positive on the left.

[0137] The following text describes the photovoltaic module 6 in detail with the left side negative and the right side positive.

[0138] The positive terminals of the first battery string group 641 and the second battery string group 642 face outwards, while the negative terminals of the third battery string group 643, the fourth battery string group 644, the fifth battery string group 645, and the sixth battery string group 646 face outwards, also facing outwards. The negative terminals of the first battery string group 641 and the second battery string group 642 are connected to the intermediate busbar 61 to form a first contact 611. The positive terminals of the first battery string group 641 and the second battery string group 642 are connected via the first jumper busbar 62, so that the first battery string group 641 and the second battery string group 642 are connected in parallel. Simultaneously, the first jumper busbar 62 is connected to the intermediate busbar 61 to form a second contact 612. A first diode 65 for protection is connected in series between the first contact 611 and the second contact 612.

[0139] Similarly, the positive terminals of the third battery string group 643 and the fourth battery string group 644 are connected to the intermediate busbar 61 to form the third contact 613, and the negative terminals of the third battery string group 643 and the fourth battery string group 644 are connected in parallel via the first jumper busbar 62. Meanwhile, a second diode 66 for protection is connected in series between the second contact 612 and the third contact 613.

[0140] Furthermore, the electrodes of the first battery string group 641 connected at the first contact 611 have opposite polarities to the electrodes of the third battery string group 643 connected at the third contact 613. The first battery string group 641 and the third battery string group 643 are connected in series via the first jumper bus bar 62. The first battery string group 641 and the third battery string group 643 share the first jumper bus bar 62, which helps to reduce power loss.

[0141] Similarly, the positive terminals of the fifth battery string group 645 and the sixth battery string group 646 are connected to the intermediate busbar 61 to form the fourth contact 614. The negative terminals of the fifth battery string group 645 and the sixth battery string group 646 are connected in parallel via the second jumper busbar 63, and the second jumper busbar 63 is connected to the intermediate busbar 61 to form the fifth contact 615. A third diode 67 for protection is connected in series between the fourth contact 614 and the fifth contact 615. The electrode of the third battery string group 643 connected to the third contact 613 has the same polarity as the electrode of the fifth battery string group 645 connected to the fourth contact 614. The third battery string group 643 and the fifth battery string group 645 are connected in series via the second jumper busbar 63.

[0142] The above descriptions are merely specific implementations of the embodiments of this application, but the protection scope of the embodiments of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the embodiments of this application should be covered within the protection scope of the embodiments of this application. Therefore, the protection scope of the embodiments of this application should be determined by the protection scope of the claims.

Claims

1. A method for preparing a battery cell, characterized in that, The method for preparing the battery cell includes at least the following steps: Provide a complete battery (1); At least one cutting line (11) is positioned on the surface of the entire battery (1). An isolation portion (5) is prepared on the surface of the whole battery (1) along both sides near at least one of the cutting lines (11). The entire cell (1) is laser-cut along at least one of the cutting lines (11) to form at least two cell segments (2). At least two of the said segmented cells (2) are stacked along the thickness direction of the segmented cells (2) so that the cut surfaces (21) of each of the segmented cells (2) are stacked to form a cross section (3), and a passivation layer (4) is deposited on the cross section (3). Along the direction perpendicular to the cutting surface (21), the distance L1 between the edge of the isolation part (5) near the cutting surface (21) and the cutting surface (21) satisfies: L1≤1mm.

2. The method for preparing a battery cell according to claim 1, characterized in that, The material of the isolation part (5) is silicone or acrylic.

3. The method for preparing the battery cell according to claim 1, characterized in that, Along the direction perpendicular to the cut surface (21), the ratio of the dimension L2 of the isolation portion (5) to the dimension L3 of the segmented battery (2) satisfies: 3.2 10 -5 ≤L2 / L3≤2.5 10 -3 .

4. The method for preparing a battery cell according to claim 2, characterized in that, The dimension L2 of the isolation part (5) in the direction perpendicular to the cutting surface (21) satisfies: 5um≤L2≤200um.

5. The method for preparing a battery cell according to claim 1, characterized in that, The dimension D of the isolation part (5) along the thickness direction of the segmented battery (2) satisfies: 1um≤D≤20um.

6. The method for preparing a battery cell according to claim 1, characterized in that, Along the direction perpendicular to the cut surface (21), the plating dimension F satisfies: F≤1mm.

7. The method for preparing a battery cell according to any one of claims 1-6, characterized in that, In the step of positioning at least one cutting line (11) on the surface of the entire battery cell (1), the method for preparing the battery cell includes the following steps: At least two of the cutting lines (11) are positioned on the surface of the entire battery (1). In the step of preparing the insulating portion (5) on both sides of the surface of the entire battery cell (1) near at least one of the cutting lines (11), the method for preparing the battery cell includes the following steps: The insulating portion (5) is prepared at both edge positions of the entire battery (1) along the direction of the cutting line (11).

8. The method for preparing a battery cell according to any one of claims 1-6, characterized in that, During laser cutting, the grooving power W1 satisfies: 0.1W≤W1≤150W, the grooving frequency Q satisfies: 60kHz≤Q≤100kHz, the thermal cracking power W2 satisfies: 0.05W≤W2≤50W, and the cutting speed V satisfies: 500mm / s≤V≤800mm / s.

9. The method for preparing a battery cell according to any one of claims 1-6, characterized in that, Along the direction perpendicular to the cut surface (21), the size H of the passivation layer (4) satisfies: 30nm≤H≤65nm. During the deposition of the passivation layer (4), the deposition temperature T satisfies: 200℃≤T≤300℃, and the deposition time R satisfies: 2h≤R≤4h.

10. A battery cell, characterized in that, The battery cell is prepared based on the preparation method of the battery cell according to any one of claims 1-9; The battery cell can be a back contact battery or a tunnel oxide passivated contact battery, and the isolation part (5) is disposed on the front side of the battery cell.

11. A photovoltaic module, characterized in that, The photovoltaic module (6) includes the solar cell as described in claim 10.

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