Laser sintering equipment, LECO machine table and method for processing 0BB battery

Abstract

The invention provides laser sintering equipment, an LECO machine table and a method for processing an 0BB battery. The equipment comprises an outer frame, probe frames are arranged on the outer frame, and at least two rows of probes are distributed on each probe frame; and all the probes are mounted on the probe frame in a detachable manner. According to the laser sintering equipment provided by the invention, at least two rows of probes are distributed on each probe frame, so that the problem that a single probe row cannot reach partial auxiliary grid voltage can be relieved to a great extent, the fill factor FF can be improved, the contact resistance can be reduced, and the overall performance of a battery is improved. In addition, the design of two rows of probes is adopted, the density of the probes can be increased, and the machining precision and stability can be improved. Moreover, the design of the two rows of probes can also improve the processing stability, so that each battery can obtain a consistent processing effect, thereby improving the quality and consistency of products.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a laser sintering device, a LECO machine, and a method for processing an 0BB battery. Background Art

[0002] The mainstream product of the current production line is SMBB (Super Multi Busbar) batteries. However, as the number of busbars increases, SMBB batteries not only increase silver consumption and non-silicon costs, but also increase the shading area and reduce optical utilization. In order to further reduce costs by removing silver, the market research and development direction is moving towards 0BB (no busbar) battery technology.

[0003] LECO (Laser-enhanced contact optimization) process is an advanced laser sintering technology, especially suitable for solar cells with SMBB (Super Multi Busbar) structure, such as 16BB, 18BB, 20BB and 24BB. The LECO process irradiates the cell with high-intensity laser, and applies deflection voltage to the main grid of the SMBB cell through the probe, so that current is formed through the main grid to each sub-grid of the SMBB cell, and then a high temperature is formed through the high-resistance area, so as to achieve laser sintering and enable silver to directly contact silicon. Without damaging the silicon wafer, the silver paste is locally melted and diffused into the surface of the silicon wafer to form a tiny silver-silicon alloy junction. This alloy junction has a very low contact resistance, thereby effectively reducing the contact resistance of the SMBB cell.

[0004] However, in the process of processing 0BB batteries using the LECO process, since 0BB batteries have no main grid but only sub-grids, and the spacing between the sub-grids is relatively dense, if the existing laser sintering equipment for processing SMBB batteries is used to process 0BB batteries, some of the sub-grids will not be pressed by the probe, so the sub-grids cannot form current, and it is impossible to form a higher temperature through the high-resistance area to achieve laser sintering, resulting in a higher contact resistance for the processed 0BB battery. Summary of the invention

[0005] The present invention provides a laser sintering device, a LECO machine, and a method for processing a 0BB battery, so as to solve the defect of processing the 0BB battery in the prior art, which leads to a high contact resistance, and effectively reduce the contact resistance of the 0BB battery through the LECO process.

[0006] A laser sintering device comprises: an outer frame, on which a probe rack is arranged, and on each probe rack at least two rows of probes are distributed;

[0007] All probes are detachably mounted on the probe rack.

[0008] Further, according to the laser sintering equipment as described above, in the at least two rows of probes, the distance i between the centers of two adjacent probes is: 0<i≤2D; D is the diameter of the probe.

[0009] Further, according to the laser sintering device as described above, the distance i between two adjacent probes is: O<i≤1 / 2D.

[0010] Furthermore, according to the laser sintering equipment as described above, a plurality of probe racks are arranged on the outer frame.

[0011] A LECO machine comprises any of the laser sintering devices described above.

[0012] A method for processing 0BB using the LECO machine as described above, comprising:

[0013] Determine the 0BB battery graphics to be processed;

[0014] According to the 0BB battery pattern to be processed, 2 or more rows of probe racks are arranged on the outer frame, and at least 2 rows of probes are distributed on each probe rack;

[0015] The probe is used to apply a deflection voltage to the sub-grid of the 0BB battery, and the laser is used to irradiate the target area of ​​the 0BB battery to achieve the processing of the 0BB battery.

[0016] Furthermore, according to the method described above, the deflection voltage range applied to the auxiliary grid of the 0BB battery is: 12-28V.

[0017] Furthermore, according to the method described above, on the left and right sides of the probe holder, the target area of ​​the 0BB battery is irradiated with laser to achieve sintering.

[0018] The laser sintering equipment, LECO machine, and method for processing 0BB battery provided by the present invention can greatly alleviate the problem of insufficient voltage actually applied to a single probe row by distributing at least 2 rows of probes on each probe rack, and can also improve the filling factor FF, reduce the contact resistance, and thus improve the overall performance of the battery. In addition, the present invention adopts the design of two rows of probes, which can not only increase the density of the probes, but also improve the precision and stability of the processing. Since the two rows of probes can be more evenly distributed on the battery sheet, the position and range of laser sintering can be more accurately controlled to avoid over-burning or under-burning. Moreover, the design of two rows of probes can also improve the stability of the processing, so that each battery can obtain a consistent processing effect, thereby improving the quality and consistency of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the probe distribution of existing laser sintering equipment;

[0020] Figure 2 A schematic diagram of the structure of the laser sintering equipment provided by the present invention;

[0021] Figure 3 This is a schematic diagram of the probe distribution of the present invention;

[0022] Reference numerals:

[0023] 1-probe holder; 2-outer frame; 11-probe hole; 12-probe. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] SMBB cells increase the number of main grids to 16 or more. While the number of main grids increases, thinner welding strips are used to improve the accuracy of string welding and reduce the area of ​​main grid PAD points. This can not only reduce the consumption of silver paste and reduce costs, but also reduce the current transmission distance, reduce grid line shading, improve optical utilization, effectively reduce the series resistance of the component, and maximize the use of sunlight. At present, the number of SMBB main grids of mainstream manufacturers has increased to 16-20. According to CPIA, SMBB technology with 16BB or more will account for 87.5% of TOPCon cells in 2023. However, with the increase in the number of main grids, SMBB not only brings about an increase in silver consumption and an increase in non-silicon costs, but also increases the shading area and reduces the optical utilization rate. In order to further reduce costs by removing silver, 0BB cells (no main grid cells) have appeared on the market. However, whether it is SMBB cells or OBB cells, the cells need to be further processed by laser induced sintering technology.

[0026] The so-called laser induced sintering technology refers to the use of high-energy lasers to melt and recrystallize the material on the surface of the cell (such as powder or filamentary material), or to quickly heat up the powder material to melt the particles to achieve sintering. This technology has been widely used in the field of solar cell manufacturing due to its high efficiency, high precision and high flexibility. The principle is: laser induced sintering technology mainly uses the precise control of the laser beam to stack the materials layer by layer and irradiate them with lasers at the same time to achieve rapid sintering and molding of the materials. In the process of solar cell manufacturing, this technology can accurately destroy the passivation layer on the surface of the silicon wafer, and in the process form an optimized metal / silicon contact point, thereby improving the contact between the metal electrode and the silicon wafer in the solar cell, reducing the contact resistance, and improving the conversion efficiency of the battery.

[0027] Currently, the equipment that uses the LECO process to laser sinter 0BB batteries (busbarless batteries) is all for SMBB structure batteries. Figure 1 Schematic diagram of probe distribution of existing laser sintering equipment, such as Figure 1 As shown, the device includes: a probe rack 1, on which a row of probes 12 are arranged, and the probes 12 are installed in probe holes 11. The probe rack 1 is a component for installing the probes 12, which is responsible for fixing the probes 12 in the correct position and ensuring that the probes can accurately contact the grid lines on the battery cells. The probe rack is usually made of metal with high strength and wear resistance. Its shape and size are determined according to the design and use requirements of the probes to ensure that the probe row can be stably installed on the probe rack. The probe row is one of the core components of the LECO machine, which is responsible for applying voltage to the grid lines on the battery cells to realize the laser sintering process. The row of probes arranged on the probe rack are arranged on the probe rack at a certain interval, and the material of the probes is usually a metal with good conductive properties, such as copper or silver.

[0028] However, since the 0BB battery has no main grid but only a sub-grid, all electrical conduction depends on the transmission of the fine grid, and the transmission resistance is large. If the laser sintering equipment with only one row of probes is used to process the 0BB battery, the probe may not be able to press each sub-grid, resulting in some grid lines being unable to effectively contact, resulting in a relatively large transmission resistance, affecting the performance of the 0BB battery, specifically manifested as a low fill factor FF and a high contact resistivity. In order to solve this problem, the present invention uses a laser sintering equipment including at least 2 rows of probes to process the 0BB battery, so that more sub-grids can be pressed by the probes, thereby solving the problem of large transmission resistance and high contact resistivity.

[0029] Figure 2 The schematic diagram of the laser sintering equipment provided by the present invention is as follows: Figure 2As shown, the device comprises: an outer frame 2, on which a probe rack 1 is arranged, and on each probe rack 1 at least two rows of probes 12 are distributed; all probes 12 are detachably mounted on the probe rack.

[0030] Specifically, the outer frame 2 is the basic support structure of the LECO machine, providing a foundation for the installation and fixing of other components. The outer frame is usually made of high-strength, corrosion-resistant materials, such as high-quality steel or aluminum alloy. Its shape and size are determined according to the design and use requirements of the machine to ensure the stability and durability of the machine. The outer frame is reasonably designed and has a solid structure. It can withstand large loads and vibrations, and has good heat dissipation performance to ensure that the machine maintains a stable temperature and performance during long-term operation.

[0031] The OBB battery eliminates the main grid in the battery cell link and relies only on the fine grid for electrical conduction. The use of welding strips to conduct current in the component link helps to reduce silver consumption and shading loss, thereby achieving cost reduction and efficiency improvement. However, since the 0BB battery has no main grid, all electrical conduction depends on the transmission of the secondary grid during the LECO machine process. If part of the secondary grid is not pressed, it will affect the fill factor (FF) and contact resistivity of the 0BB battery. Low fill factor FF and high contact resistivity are the main problems faced by 0BB batteries. In order to solve this problem, the present invention provides a solution of multiple probe rows, such as Figure 2 As shown, at least two rows of probes are arranged on a probe rack 2, and the number of probes in each row is at least 16. The laser sintering equipment provided by the present invention can significantly increase the density of probes by adopting a design of two rows of probes, so that each sub-grid can be effectively pressed by the probe, thereby ensuring that the current can flow smoothly through each grid line and effectively reducing the contact resistivity.

[0032] In addition, multiple rows of closely spaced probes match the laser pattern, which can better control the laser sintering process, further reduce the contact resistivity, and improve the efficiency of the battery. Table 1 shows the data results of testing 16BB cells and 0BB cells respectively, as shown in Table 1, where Eta is the battery conversion efficiency, Uoc is the opening voltage, Isc is the current, FF is the filling, Rshunt is the parallel resistance, Rser is the series resistance, ρc is the contact resistivity, and the number is the number of cells. The measured Eta, Uoc, Isc, FF, Rshunt, Rse, and ρc are the average values ​​of the corresponding total number of batteries. Taking 16BB as an example, there are 1608 16BB cells, and the corresponding Eta = 25.669% is the average battery conversion efficiency of 1608 16BB cells. Similarly, the corresponding Uoc = 0.7285V is the average opening voltage value of 1608 16BB cells. Similarly, for the first row of 0BB batteries, the corresponding Eta=25.364% is the average battery conversion efficiency of 50 0BB battery cells. Similarly, the corresponding Uoc=0.7284V is the average opening voltage value of 50 0BB battery cells.

[0033] As can be seen from Table 1, if the 0BB battery is sintered using a single-row probe laser sintering device, its battery conversion efficiency is up to 25.633%, the corresponding bias voltage is 25V, and the contact resistivity is 5.26Ω*cm2. In order to reduce its contact resistivity to 4.42Ω*cm 2 , then the bias voltage needs to be adjusted to 28V, and the corresponding battery conversion efficiency is 25.347%, and the EL and appearance of the battery cell are abnormal. It can be seen that the battery conversion efficiency has not been significantly improved. When the laser sintering equipment with a double-row probe structure is used to process its 0BB battery, when the battery conversion efficiency is 25.674, its bias voltage is 21, and the contact resistivity at this time is reduced by 3.88. It can be seen that the use of double-row probes to process 0BB batteries can effectively reduce the contact resistivity when the battery conversion efficiency is not much different. If three rows of probes are used, similar effects can be basically achieved, that is, when the battery conversion efficiency is basically the same, the contact resistivity is reduced to 4.06.

[0034] Table 1

[0035]

[0036] In the embodiment of the present invention, two rows of probes are arranged on a probe rack, and each row of probes has 32 probes.

[0037] The laser sintering equipment provided by the present invention can greatly alleviate the problem of insufficient actual applied voltage encountered by a single probe row by distributing at least two rows of probes on each probe rack, and can also improve the fill factor FF, reduce contact resistance, and thus improve the overall performance of the battery. In addition, the present invention adopts a design of two rows of probes, which can not only increase the density of the probes, but also improve the accuracy and stability of processing. Since the two rows of probes can be more evenly distributed on the battery cells, the position and range of laser sintering can be more accurately controlled, thereby avoiding overburning or underburning. Moreover, the design of two rows of probes can also improve the stability of processing, so that each battery can obtain a consistent processing effect, thereby improving the quality and consistency of the product.

[0038] Furthermore, a plurality of probe racks 1 are arranged on the outer frame 3 .

[0039] Specifically, during the processing of the 0BB battery, the current formed by its secondary grid is I=U / R, where R=ρ*L / S, and L is the length of the secondary grid forming the current. When a single probe rack is used to process the 0BB battery, the length L of the secondary grid forming the current away from the probe rack area is lengthened, resulting in increased resistance, which in turn leads to a smaller current formed by the secondary grid, and the smaller current formed by the secondary grid will eventually lead to an increase in contact resistivity. Therefore, in order to further reduce the contact resistivity, the present invention provides at least two probe racks on the outer frame 3, and each probe rack is provided with multiple rows of probes, so that the contact resistivity can be further effectively reduced.

[0040] The present invention arranges a plurality of probe racks on the outer frame 1. On the one hand, it is equivalent to processing a plurality of sintering points in parallel through a plurality of probe racks, which significantly improves the sintering efficiency, which helps to shorten the production cycle and improve the overall production capacity of the OBB battery. Moreover, under the design of multiple probe racks, each probe rack can perform sintering operations independently, reducing the waiting time caused by the limited processing speed of a single probe rack. On the other hand, by pressing a plurality of probes on the sub-grid at the same time, it can ensure that the laser energy is more evenly distributed on the battery cell, reducing the sintering quality problems caused by local overheating or insufficient heating. Moreover, since the thermal stress generated during the laser sintering process is an important factor affecting the performance of the cell, the multi-probe frame design can reduce the thermal stress through more uniform heating, thereby improving the stability and reliability of the cell; on the other hand, after the multi-probes are pressed on the cell surface, the distance of the fine grid transmission is shortened, making the distance between the processing area and the probe row closer, which helps to alleviate the voltage loss problem caused by the long-distance transmission of the fine grid and reduce the contact resistivity; and due to the improvement of sintering quality and the reduction of contact resistance, the multi-probe frame design helps to improve the fill factor (FF) of the cell, which is an important indicator for evaluating the performance of solar cells. On the other hand, the multi-row probe design can more easily adapt to cells of different formats, improve the flexibility and adaptability of production, and reduce the production capacity loss when the production line changes the format.

[0041] Furthermore, in the at least two rows of probes, the distance i between the centers of two adjacent probes is: 0<i≤2D; D is the diameter of the probe.

[0042] Specifically, when the distance between the centers of two adjacent probes is two probe diameters, the interference between adjacent probes can be effectively reduced, which helps to ensure that each probe can independently and accurately complete its detection task, thereby improving the accuracy of the overall test.

[0043] Furthermore, the distance i between the centers of two adjacent probes is: 0<i≤1 / 2 probe diameter.

[0044] Specifically, the present invention reduces the distance between the centers of two adjacent probes to 1 / 2 of the probe diameter so that during the laser sintering process, the laser energy can be more evenly distributed on the battery cell, thereby achieving a more uniform sintering effect, which helps to reduce the unevenness in the sintering process and improve the overall performance of the battery cell.

[0045] Furthermore, the present invention also provides a LECO machine, which includes the laser sintering equipment as described above.

[0046] Specifically, the LECO machine includes: an outer frame, a probe rack and probe row, a laser sintering system and other components.

[0047] Among them, the laser sintering system is one of the key components of the LECO machine. It uses the high energy density characteristics of the laser to sinter the grid lines on the battery cell with materials such as silver paste to form a conductive channel. The laser sintering system is usually composed of lasers, optical systems, control systems and other parts. The laser generates a high-energy-density laser beam, the optical system is responsible for focusing the laser beam to a specified position on the battery cell, and the control system is responsible for controlling parameters such as the switch, power and movement speed of the laser beam.

[0048] Other components include:

[0049] Power supply system: Provides stable power supply for LECO machines to ensure the normal operation of the machines.

[0050] Cooling system: used to dissipate heat and reduce temperature to ensure that the machine will not be damaged due to overheating during long-term operation.

[0051] Control system: responsible for controlling the overall operation of the LECO machine, including the movement of the probe holder, the switching of the laser sintering system, and parameter adjustment.

[0052] In summary, the LECO machine has a precise structural design and powerful functions, which can achieve precise processing and efficient sintering of 0BB busbarless batteries.

[0053] The present invention also provides a method for processing 0BB using the LECO machine as described above, comprising the following steps:

[0054] Step 101: Determine the 0BB battery pattern to be processed.

[0055] Specifically, first, the 0BB battery pattern to be processed needs to be determined according to production requirements. This step usually involves determining key parameters such as the size, shape, and grid line layout of the battery cell. Then the laser scanning pattern is designed based on the pattern size, probe row distribution, etc.

[0056] Step 102: Distribute corresponding probe rows on the probe rack according to the 0BB battery pattern to be processed.

[0057] Specifically, according to the input 0BB battery pattern, the probe holder on the LECO machine is adjusted. This may involve adjusting parameters such as the position, angle and height of the probe holder to ensure that the probe can accurately contact the grid line on the battery sheet.

[0058] Probe row distribution: distribute the corresponding probe rows on the probe rack. This step needs to determine the number, spacing and arrangement of the probes according to the grid line layout of the battery pattern. For 0BB busbarless batteries, since there is no busbar, in order to ensure that the probes can cover every secondary grid line, at least two rows of probes are distributed on the probe rack.

[0059] Probe calibration: After the probe row is distributed, the probe calibration work is carried out. This includes checking the contact condition, conductivity and position accuracy of the probe to ensure that the probe can work stably and accurately during the processing.

[0060] Step 103: Apply a deflection voltage to the secondary grid of the OBB battery through a probe, and irradiate the target area of ​​the OBB battery with a laser to achieve processing of the OBB battery.

[0061] Specifically, laser irradiation: while applying a deflection voltage, the target area of ​​the 0BB battery is irradiated by laser. After laser irradiation, a high concentration of carriers can be generated on the surface of the battery. Applying a deflection voltage: applying a deflection voltage to the secondary grid of the 0BB battery through a probe, thereby generating a current of several amperes.

[0062] Processing monitoring: During the processing, the operating status of the LECO machine needs to be monitored in real time. This includes the contact of the probe, the irradiation of the laser, the applied bias voltage, etc. If an abnormality is found, the processing needs to be stopped immediately and checked and handled.

[0063] Processing completed: When all target areas have been laser sintered, the processing is complete. At this point, the processed 0BB battery can be taken out for subsequent inspection and testing.

[0064] Furthermore, the deflection voltage range applied to the auxiliary grid of the 0BB battery in the present invention is: 12-28V.

[0065] Furthermore, in order to improve the efficiency of laser sintering, the present invention irradiates the target area of ​​the 0BB battery with laser on the left and right sides of the probe frame to achieve sintering.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A laser sintering device, characterized in that: include: An outer frame (3), wherein a probe rack (1) is arranged on the outer frame (3), and at least two rows of probes (12) are distributed on each probe rack (1); All probes (12) are detachably mounted on the probe rack.

2. The laser sintering equipment according to claim 1, characterized in that: A plurality of probe racks (1) are arranged on the outer frame (3).

3. The laser sintering equipment according to claim 1, characterized in that: In the at least two rows of probes, the distance i between the centers of two adjacent probes (12) is: 0<i≤2D; D is the diameter of the probe.

4. The laser sintering equipment according to claim 2, characterized in that: The distance i between two adjacent probes (12) is: 0<i≤1 / 2D.

5. A LECO machine, characterized in that: The invention comprises the laser sintering equipment as described in any one of claims 1 to 4.

6. A method for processing 0BB using the LECO machine according to claim 5, characterized in that: include: Determine the 0BB battery graphics to be processed; According to the 0BB battery pattern to be processed, corresponding probe rows are distributed on the probe rack; The probe is used to apply a deflection voltage to the sub-grid of the 0BB battery, and the laser is used to irradiate the target area of ​​the 0BB battery to achieve the processing of the 0BB battery.

7. The method according to claim 6, characterized in that The deflection voltage range applied to the secondary grid of the 0BB battery is: 12-28V.

8. The method according to claim 6, characterized in that On the left and right sides of the probe holder, the target area of ​​the 0BB battery is irradiated by laser to achieve sintering.

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