A contactless laser-assisted sintering apparatus and a laser-assisted sintering method

Abstract

The application relates to the technical field of photovoltaic cell production, and discloses a non-contact laser-assisted sintering device and a laser-assisted sintering method. The non-contact laser-assisted sintering device comprises a workbench, and a conductive table is arranged on the workbench and used for bearing a cell piece; a laser scanning piece for laser scanning of the cell piece is arranged above the workbench; and electron beam conductive assemblies are arranged on the two sides of the laser scanning piece, so that the electron beam conductive assemblies emit electron beams to the front surface of the cell piece to generate a conductive current and form a closed loop with the conductive table on the back surface of the cell piece, thereby providing a stable 5-12V bias voltage for laser-assisted sintering. The non-contact laser-assisted sintering device can further reduce the fragment rate, improve the production capacity, simplify the structure, reduce the cost, and has better sintering consistency, and can further improve the contact optimization effect of laser-assisted sintering.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cell production technology, specifically to a non-contact laser-assisted sintering equipment and a laser-assisted sintering method. Background Technology

[0002] Applying a reverse voltage to a photovoltaic cell (hereinafter referred to as a cell) and then scanning the grid electrodes with a laser can significantly reduce the contact resistance between the grid electrodes and the silicon wafer, thereby improving the photoelectric conversion efficiency of the cell. This is the laser-assisted sintering technology currently used in the photovoltaic field to reduce the contact resistance between metal and semiconductor. In current laser-assisted sintering technologies, a reverse voltage is applied to the cell via a pressing probe during laser scanning (as shown in publication number CN117650198A). This presents two significant drawbacks: 1. Due to the obstruction of the probe, a single laser assembly cannot completely scan the entire front surface of the solar cell in one go. Therefore, it is usually necessary to equip two sets of laser assemblies, with each set scanning half of the solar cell, in order to achieve the purpose of completely scanning the entire front surface of the solar cell. However, equipping two sets of laser assemblies will undoubtedly lead to a more complex equipment structure and increase the equipment investment cost.

[0003] 2. Correspondingly, the pressing probes need to perform two actions: for example, when one set of laser modules scans the left half of the solar cell, one set of probes presses down to press the grid lines on the right side of the cell; then, this set of probes rises and retracts, transferring the cell to the second processing station; when another set of laser modules scans the right half of the solar cell, another set of probes presses down to press the grid lines on the left side of the cell; then, this other set of probes rises and retracts. Therefore, the sequential pressing and retraction actions of the two sets of probes (these four mechanical actions) prolong the process of laser-assisted sintering technology, leading to reduced production capacity. Moreover, the probes need to perform multiple pressing actions, which can easily crush or crack the solar cells, resulting in a significant increase in the breakage rate and low yield.

[0004] Furthermore, as shown in publication CN119947304A, if a suspension bridge structure (including conductive wires and drive components) is used as the pressure application component, although it can reduce the investment cost of laser components, achieve single laser scanning, increase production capacity, and reduce the breakage rate to some extent, the conductive wires (such as metal wires) will still partially obscure the grid electrodes. These grid electrodes obscured by the metal wires cannot be scanned by the laser during a single laser scan, which will reduce energy utilization and prevent truly interference-free processing. Therefore, it will affect sintering efficiency and sintering uniformity, and affect the contact optimization effect of laser-assisted sintering. Moreover, if the metal wires are too thin (the equivalent diameter of the conductive wires is 1μm-1mm), they are prone to breakage, which may affect the stability of the processing and increase the cost of metal wire consumables. In addition, the metal wires also need to apply pressure to the solar cells to apply reverse voltage. The pressing action of the metal wires will still increase the breakage rate to some extent, and cannot eliminate the solar cell breakage rate caused by the application of reverse voltage at the source. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a non-contact laser-assisted sintering device and a laser-assisted sintering method.

[0006] Based on this, the present invention discloses a non-contact laser-assisted sintering equipment, including a worktable, on which a conductive platform for supporting battery cells is provided; a laser scanning device for laser scanning of battery cells is installed above the worktable. Electron beam conductive components are installed on both sides of the laser scanning component. During laser scanning, the electron beam conductive components emit an electron beam to the front of the cell to generate a conductive current, which forms a closed loop with the conductive platform on the back of the cell, providing a stable 5-12V bias voltage for laser-assisted sintering.

[0007] Preferably, the number of electron beam conductive components is two sets; the two sets of electron beam conductive components are symmetrically distributed on the left and right sides of the laser scanning component.

[0008] Preferably, the electron beam conductive component includes an electron gun, a weak vacuum chamber, and a current-limiting orifice; the electron gun is mounted inside the weak vacuum chamber at the top and is connected to an external driving power supply; a vacuum pump is connected outside the weak vacuum chamber to maintain a weak vacuum of 0.1-1 Pa inside the weak vacuum chamber; several current-limiting orifices with an equivalent aperture of 0.5-2 mm are opened at the lower end of the weak vacuum chamber, so that the electron beam emitted by the electron gun passes through the weak vacuum chamber and the current-limiting orifice in sequence and then exits and reaches the front of the solar cell.

[0009] More preferably, the electron beam current density emitted by the electron gun is greater than or equal to 10. -9 A / cm², and less than 10-6 A / cm², the accelerating voltage of the electron gun is 5-12V, and the distance between the electron gun and the current-limiting orifice is 4-6cm.

[0010] More preferably, the electron beam of the electron beam conductive component corresponds to the grid line area on the front side of the battery cell.

[0011] More preferably, the electron beam conductive component emits an electron beam to the edge grid line on the front side of the battery cell, and the distance between the outlet of the current limiting aperture and the edge grid line on the front side of the battery cell is 2-4 mm.

[0012] Preferably, the conductive platform is a metal conductive platform, which is a copper platform, an aluminum platform, or a silver platform.

[0013] Preferably, the worktable is a rotary worktable with a plurality of conductive surfaces spaced apart circumferentially, or a linear transmission worktable with a plurality of conductive surfaces spaced along the transmission direction.

[0014] This invention also discloses a non-contact laser-assisted sintering method, which operates using the non-contact laser-assisted sintering equipment described above, and includes the following steps: S1. Divide the front of the battery cell into a first region and a second region, and place the battery cell on a conductive platform; S2. The first region is laser-scanned, and the electron beam conductive component located on one side of the laser scanning component emits an electron beam to the second region on the front side of the cell to generate a conductive current to form a closed loop with the conductive platform in contact with the back side of the cell, so as to provide a bias voltage to perform laser-assisted sintering on the first region. S3. The second region is laser-scanned, and the electron beam conductive component located on the other side of the laser-scanning component emits an electron beam to the first region on the front side of the cell to generate a conductive current to form a closed loop with the conductive platform in contact with the back side of the cell, so as to provide a bias voltage for laser-assisted sintering of the second region.

[0015] Preferably, in steps S2 and S3, the laser scanning element uses a 1054-1074nm infrared light source, employs a Gaussian spot, has a power matching range of 10-50W, and a scanning speed of 10-20m / s. Preferably, in steps S2 and S3, the weak vacuum level in the weak vacuum cavity of the electron beam conductive component is maintained at 0.1-1 Pa, and the electron beam current density emitted by the electron gun is greater than or equal to 10. -9 A / cm², and less than 10 -6A / cm², the accelerating voltage of the electron gun is 5-12V, the equivalent aperture of the current limiting orifice is 0.5-2mm, the distance between the electron gun and the current limiting orifice is 4-6cm, and the distance between the outlet of the current limiting orifice and the edge grid line on the front of the cell is 2-4mm.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: The contactless laser-assisted sintering equipment of the present invention applies a contactless reverse voltage (bias voltage) to the front side of the solar cell by using an electron beam conductive component with a conductive platform. It only requires one set of laser scanning components, which can reduce equipment costs. It also effectively avoids the probe pressing action in existing laser-assisted sintering equipment, fundamentally eliminating the risk of microcracks and fragmentation of solar cells caused by existing probe pressing (mechanical contact), and significantly reducing the fragmentation rate. At the same time, the bias voltage application of its efficient electron beam conductive component also saves the mechanical action of multiple pressing and retraction of existing probe pressing, improving the processing cycle and overall production capacity.

[0017] Moreover, existing metal wire replacement solutions, such as those in CN119947304A, still partially obstruct the laser beam, preventing truly interference-free processing and affecting sintering uniformity. Furthermore, the metal wires are thin, prone to breakage, and have high material costs. Additionally, the metal wires still require downward pressure to apply a bias voltage to the solar cells, posing a significant risk of breakage. In contrast to the metal wire replacement solution in CN119947304A, this invention completely avoids the inherent defects of existing contact-based downward pressure bias voltage application methods, offering the following advantages: Compared to the metal wire alternative in CN119947304A, (1) the non-contact laser-assisted sintering equipment of the present invention achieves true non-contact bias voltage application by using an electron beam conductive component with a conductive platform. The electron beam is not physically blocked, resulting in better sintering consistency and further improving the contact optimization effect of laser-assisted sintering; (2) it avoids the material costs caused by the thinness and easy breakage of metal wires, and can further reduce costs; (3) the non-contact laser-assisted sintering equipment greatly reduces the breakage rate and hidden cracks caused by the downward application of bias voltage from the root, and can further reduce the breakage rate. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural diagram of a non-contact laser-assisted sintering device according to the present invention.

[0019] Figure 2 This is a schematic diagram of the electron beam conductive component of the present invention.

[0020] Figure 3 This is a cross-sectional structural diagram of the electron beam conductive component of the present invention.

[0021] Figure 4 for Figure 2 A bottom view of the current-limiting orifice of the electron beam conductive component.

[0022] Figure 5 This is an EL image of the battery cell in Example 1 after non-contact laser-assisted sintering.

[0023] Figure 6 This is an EL image of the battery cell in Example 2 after non-contact laser-assisted sintering.

[0024] Figure 7 This is an EL image of the solar cell in Comparative Example 1 after non-contact laser-assisted sintering.

[0025] Figure 8 This is an EL image of the solar cell in Comparative Example 2 after non-contact laser-assisted sintering.

[0026] The reference numerals are as follows: 1. Worktable; 2. Conductive surface; 3. Battery cell; 4. Laser scanning component; 5. Electron beam conductive assembly; 51. Electron gun; 52. Weak vacuum chamber; 53. Flow limiting orifice; 54. Vacuum pump. Detailed Implementation

[0027] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] This invention relates to a contactless laser-assisted sintering device, see [link to relevant documentation]. Figure 1 The system includes a worktable 1, on which a conductive platform 2 for supporting the battery cell 3 is provided; a laser scanning component 4 for laser scanning of the battery cell 3 is installed above the worktable 1; electron beam conductive components 5 are installed on both sides of the laser scanning component 4 so that during laser scanning, the electron beam conductive components 5 emit an electron beam to the front of the battery cell 3 to generate a conductive current, thereby forming a closed circuit with the conductive platform 2 on the back of the battery cell 3, and providing a stable 5-12V bias voltage for laser-assisted sintering.

[0029] The conductive mesa 2 is a metal conductive mesa (such as a copper, aluminum, or silver mesa, preferably a copper mesa). The metal conductive mesa is used to support the battery cell 3 and for conducting electricity; silver has better conductivity but is more expensive; aluminum is also an option, but its conductivity is not as good as silver or copper. Therefore, a copper mesa is preferred.

[0030] Preferably, the laser scanning element 4 is mounted directly above the worktable 1. The number of electron beam conductive components 5 is preferably two sets. The two sets of electron beam conductive components 5 are symmetrically distributed on the left and right sides of the laser scanning element 4. Thus, through the coordinated operation of one laser scanning element 4 and two sets of electron beam conductive components 5, the working area of ​​the electron beam conductive components 5 and the scanning area of ​​the laser scanning element 4 can remain independent and non-overlapping. The electron beam conductive components 5 will not obstruct the laser scanning path, and the laser will not directly shine on the electron beam conductive components 5. In the non-contact laser-assisted sintering process, the laser scanning element 4 and the electron beam conductive components 5 are completely spatially offset, and their working processes do not affect each other, stably achieving the coordinated operation of laser-assisted sintering and non-contact electron beam conductivity.

[0031] Specifically, see Figure 2-4 The electron beam conductive component 5 includes an electron gun 51, a weak vacuum chamber 52, and a current-limiting orifice 53. The electron gun 51 is mounted inside and above the weak vacuum chamber 52; the electron gun 51 is connected to an external driving power supply, which provides the operating voltage to the electron gun 51. A vacuum pump 54 is externally connected to the weak vacuum chamber 52 to maintain a weak vacuum level of 0.1-1 Pa within the chamber. The vacuum level within the weak vacuum chamber 52 is preferably limited to 0.1-1 Pa. If the vacuum level is too low, electron beam scattering is severe, making stable transmission impossible and affecting the contactless application of the bias voltage; if the vacuum level is too high, it increases equipment cost and structural complexity.

[0032] Furthermore, the lower end of the weak vacuum chamber 52 is provided with several spaced-apart current-limiting orifices 53 with an equivalent aperture of 0.5-2 mm (preferably 1-3 orifices 53 for each group of electron beam conductive components 5), so that the electron beam emitted by the electron gun 51 passes through the weak vacuum chamber 52 and the current-limiting orifices 53 sequentially before exiting and reaching the front side of the battery cell 3. The equivalent aperture of the current-limiting orifice 53 is preferably limited to 0.5-2 mm. If the equivalent aperture of the current-limiting orifice is too small, it is easy to clog, resulting in low electron beam throughput and affecting the non-contact application of the bias voltage; if the equivalent aperture of the current-limiting orifice is too large, it will cause a significant increase in the leakage of gas inside the weak vacuum chamber 52, making it impossible to maintain the target vacuum level.

[0033] Furthermore, the electron beam current density emitted by the electron gun 51 is greater than or equal to 10. -9 A / cm², and less than 10 - 6 A / cm². Electron beam current density is less than 10 A / cm². -9At a density of A / cm², the number of charge carriers injected per unit area into the solar cell 3 is insufficient, making it impossible to form a stable conductive channel on the surface of the solar cell 3. This results in insufficient closed-loop conductivity, ineffective bias voltage establishment, a significant decrease in laser-assisted sintering effect, and ineffective improvement of the contact resistance of the solar cell 3. For example, using the same laser scanning parameters and maintaining the same accelerating voltage for the solar cell 3 and electron gun 51, only changing the electron beam current density: when the electron beam current density is less than 10... -9 At A / cm², the circuit conduction is unstable, and the contact resistance of cell 3 after sintering is relatively high, close to that of the unbiased voltage state. When the current density is greater than or equal to 10... -9 At A / cm², the circuit conduction is stable, the contact resistance of cell 3 is significantly reduced, and the sintering effect meets the requirements.

[0034] Of course, there is an upper limit to the electron beam current density, and it cannot be increased indefinitely. Excessive electron beam current density will cause localized overheating on the surface of cell 3 (or silicon wafer), resulting in grid line ablation and thermal damage to the silicon wafer; excessively high beam current can also easily lead to PN junction breakdown in cell 3, affecting the electrical performance of cell 3. The upper limit for electron beam current density is 10. -6 A / cm² (electron beam current density greater than or equal to 10) -9 A / cm², and less than 10 -6 Exceeding this current density range (A / cm²) will directly cause silicon wafer defects.

[0035] The distance between the electron gun 51 and the current-limiting orifice 53 is 4-6 cm (vacuum transmission distance), and the accelerating voltage of the electron gun 51 is 5-12V. The electron beam propagates along a 4-6 cm vacuum path within the weak vacuum cavity 52, enters the ambient temperature and pressure region through the current-limiting orifice 53, which is located at a certain position above the solar cell 3. The electron beam reaches a fixed position (such as the grid area) on the front side of the solar cell 3 within a certain distance from the outlet of the current-limiting orifice 53, thus achieving contactless conductivity. The accelerating voltage of the electron gun 51 is limited to 5-12V. Too low an accelerating voltage will prevent effective electron emission; too high an accelerating voltage will cause breakdown and damage to the silicon wafer surface.

[0036] In practice, the electron beam conductive component 5 emits an electron beam to the grid line area on the front side of the solar cell 3. Further, the electron beam conductive component 5 emits an electron beam to the edge grid line on the front side of the solar cell 3, and the distance from the outlet of the current-limiting aperture 53 to the edge grid line on the front side of the solar cell 3 is 2-4 mm. The distance between the outlet of the current-limiting aperture 53 and the edge grid line on the front side of the solar cell 3 is limited to the range of 2-4 mm; that is, the outlet of the current-limiting aperture 53 is located within 2-4 mm diagonally above the outermost grid line on the front side of the solar cell 3 (such as the left or right edge grid line), while the outermost grid line on the front side of the solar cell 3 is about 1 mm from the edge of the solar cell 3. If the distance between the outlet of the current-limiting aperture 53 and the edge grid line on the front side of the solar cell 3 is too large, the electron beam will attenuate significantly under normal pressure, making effective conduction impossible; if the distance between the outlet of the current-limiting aperture 53 and the edge grid line on the front side of the solar cell 3 is too small, there is a risk of silicon wafer collision.

[0037] Therefore, the working principle of the electron beam conductive component 5 in this invention is as follows: The vacuum pump 54 operates to maintain the vacuum level inside the weak vacuum chamber 52 at 0.1-1 Pa, forming a weak vacuum environment. The external driving power supply provides a 5-12V operating voltage to the electron gun 51, which emits an electron beam. The electron beam travels along a vacuum path of 4-6cm (e.g., 5cm) within the weak vacuum chamber 52 and exits through the flow-limiting orifice 53 to the ambient temperature and pressure region. The emitted electron beam forms a conductive path from the outlet of the flow-limiting orifice 53 to the front edge grid line of the solar cell 3 at a distance of 2-4mm (e.g., 3mm), forming a closed loop with the conductive platform 2 on the back of the solar cell 3, providing a bias voltage for laser-assisted sintering.

[0038] In practice, the worktable 1 is a rotary worktable 1 with a plurality of conductive platforms 2 spaced apart along the circumference (e.g., Figure 1 (as shown), or a linear transmission worktable 1 with several conductive platforms 2 arranged along the transmission direction.

[0039] The present invention provides a non-contact laser-assisted sintering method, which operates using the non-contact laser-assisted sintering equipment described above, and includes the following steps: S1. Divide the front of the battery cell 3 into a first region and a second region, and place the battery cell 3 on the conductive platform 2. S2. The first region is laser-scanned, and the electron beam conductive component 5 located on one side of the laser scanning component 4 emits an electron beam to the second region on the front side of the battery cell 3 to generate a conductive current to form a closed loop with the conductive platform 2 on the back side of the battery cell 3 to provide a bias voltage for laser-assisted sintering of the first region. S3. The second region is laser-scanned, and the electron beam conductive component 5 located on the other side of the laser scanning component 4 emits an electron beam to the first region on the front side of the cell 3 to generate a conductive current to form a closed loop with the conductive platform 2 in contact with the back side of the cell 3, so as to provide a bias voltage for laser-assisted sintering of the second region.

[0040] In steps S2 and S3, the laser scanning element 4 uses a 1064nm infrared light source with a Gaussian spot, a power matching range of 10-50W, and a scanning speed of 10-20m / s.

[0041] In steps S2 and S3, the weak vacuum chamber 52 of the electron beam conductive component 5 maintains a weak vacuum level of 0.1-1 Pa, and the electron beam current density emitted by the electron gun 51 is greater than or equal to 10. -9 A / cm², and less than 10 -6 A / cm², the accelerating voltage of electron gun 51 is 5-12V, the equivalent aperture of current limiting orifice 53 is 0.5-2mm, the distance between electron gun 51 and current limiting orifice 53 is 4-6cm, and the distance between the outlet of current limiting orifice 53 and the edge grid line on the front side of battery cell 3 is 2-4mm.

[0042] In practice, the bias voltage is preferably applied at the same time as the laser scanning time, and the bias voltage is applied synchronously with the laser scanning to achieve laser-assisted sintering.

[0043] After step S3, the following steps are also included: After laser-assisted sintering is completed, the current battery cell 3 is transported out of the current working position by rotation or linear transport, and the next conductive platform 2 loaded with battery cell 3 is transported to the current working position, so as to repeat the above steps S2-S3 to achieve non-contact laser-assisted sintering of the next battery cell 3.

[0044] The following are specific embodiments of a contactless laser-assisted sintering device and a contactless laser-assisted sintering method according to the present invention.

[0045] Example 1 This embodiment provides a contactless laser-assisted sintering device and its method, referring to the specific implementation described above: In steps S2 and S3, the metal conductive platform is a copper platform; the weak vacuum chamber of the electron beam conductive component maintains a weak vacuum of 0.2 Pa; the number of current-limiting orifices is 3; the equivalent aperture of the current-limiting orifices is 1 mm; and the electron beam current density emitted by the electron gun is 1.0 × 10⁻⁶. -9The electron gun has an A / cm² capacity, a 5cm gap between itself and the current-limiting orifice, and a 3mm gap between the orifice outlet and the left (or right) edge grid line on the front of the solar cell. A 6V bias voltage is provided to the left or right edge grid line on the front of the solar cell. A 1064nm infrared light source with a Gaussian spot size is used for the laser scanning element, with a power matching range of 35W and a scanning speed of 18m / s.

[0046] Example 2 This embodiment provides a contactless laser-assisted sintering device and its contactless laser-assisted sintering method, referring to Embodiment 1. The difference between Embodiment 1 and Embodiment 1 is that in steps S2 and S3 of this embodiment, the electron beam current density of the electron beam conductive component is 8.0 × 10⁻⁶. -9 A / cm² provides an 11V bias voltage to the left or right edge grid line on the front of the solar cell.

[0047] Comparative Example 1 This comparative example provides a contactless laser-assisted sintering device and its contactless laser-assisted sintering method. Referring to Example 1, the difference between this and Example 1 is that in steps S2 and S3 of this comparative example, the electron beam current density of the electron beam conductive component is 10. - ¹ 0 A / cm² provides a 4V bias voltage to the left or right edge grid line on the front of the solar cell.

[0048] Comparative Example 2 This comparative example provides a contactless laser-assisted sintering device and method, referring to Example 1. The difference between Example 1 and Example 1 is that in steps S2 and S3 of this comparative example, the electron beam current density of the electron beam conductive component is 1×10⁻⁶. -6 A / cm² provides a 13V bias voltage to the left or right edge grid line on the front of the solar cell.

[0049] Performance testing The performance of the solar cells after non-contact laser-assisted sintering in Examples 1-2 and Comparative Examples 1-2 was tested using an EL (electroluminescence) tester (the EL tester can detect the contact quality and latent defects of the solar cells after laser-assisted sintering). The test results are as follows. Figure 5-8 As shown.

[0050] See Figure 5-8 It can be seen that the solar cells in Examples 1-2 were generally normal after non-contact laser-assisted sintering. However, the solar cell in Comparative Example 1 showed many pits after non-contact laser-assisted sintering. The solar cell in Comparative Example 2 appeared dark overall after non-contact laser-assisted sintering. The pitting and darkening indicate defects in the solar cells after non-contact laser-assisted sintering.

[0051] Therefore, to ensure better non-contact laser-assisted sintering results, the non-contact laser-assisted sintering equipment and method of the present invention should preferably control the electron beam current density of the electron beam conductive component to be greater than or equal to 10. -9 A / cm², less than 10 -6 Within the range of A / cm², and the bias voltage should preferably be controlled within the range of 5-12V.

[0052] Furthermore, existing mechanical probe pressing can cause stress to brittle materials such as photovoltaic silicon wafers or solar cells, easily leading to microcracks, breakage, and damage. This invention, however, uses a conductive platform in conjunction with an electron beam conductive component, allowing the electron beam emitted by the component to reach the front of the solar cell, achieving non-contact energy transfer. This enables truly contactless bias voltage application, completely eliminating mechanical contact and downward pressure, thus preventing stress damage and significantly reducing the breakage rate (current probe pressing solutions have a breakage rate of 0.12%, mainly due to the external force generated during probe pressing; while the non-contact laser-assisted sintering equipment of this invention achieves a breakage rate of 0.02% (mainly due to material feeding)). Moreover, with an average solar cell price of 8 yuan per cell, the non-contact laser-assisted sintering equipment can process 4000 cells per hour, saving 32 yuan per hour. The more non-contact laser-assisted sintering equipment used, the greater the cost reduction.

[0053] Compared to existing mechanical probe pressing methods, this invention uses a contactless structure to apply bias voltage, resulting in direct energy transfer, fast response, and higher processing efficiency. It can significantly shorten the processing time of a single solar cell, improving cycle time and overall production capacity. For example, when using the contactless laser-assisted sintering equipment of this invention for laser-assisted sintering, each solar cell can have its left and right probe pressing and retraction actions (a total of 4 mechanical actions) reduced by 2 seconds. Existing mechanical probe pressing methods typically require 9 seconds for laser scanning of the entire front of the solar cell. Replacing this with an electron beam from the contactless laser-assisted sintering equipment of this invention can increase production capacity by 22.22%.

[0054] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present invention.

[0055] The technical solution provided by the present invention has been described in detail above. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A non-contact laser-assisted sintering device, characterized in that, It includes a worktable with a conductive surface for supporting the battery cells; a laser scanning device for laser scanning the battery cells is mounted above the worktable. Electron beam conductive components are installed on both sides of the laser scanning component. During laser scanning, the electron beam conductive components emit an electron beam to the front of the cell to generate a conductive current, which forms a closed loop with the conductive platform on the back of the cell, providing a stable 5-12V bias voltage for laser-assisted sintering.

2. The non-contact laser-assisted sintering equipment according to claim 1, characterized in that, The number of electron beam conductive components is two sets; the two sets of electron beam conductive components are symmetrically distributed on the left and right sides of the laser scanning component.

3. The non-contact laser-assisted sintering equipment according to claim 1, characterized in that, The electron beam conductive component includes an electron gun, a weak vacuum chamber, and a current-limiting orifice. The electron gun is mounted inside the weak vacuum chamber at the top and is connected to an external driving power supply. A vacuum pump is connected outside the weak vacuum chamber to maintain a weak vacuum of 0.1-1 Pa inside the chamber. Several current-limiting orifices with an equivalent aperture of 0.5-2 mm are spaced apart at the lower end of the weak vacuum chamber so that the electron beam emitted by the electron gun passes through the weak vacuum chamber and the current-limiting orifice in sequence before exiting and reaching the front of the solar cell.

4. The non-contact laser-assisted sintering equipment according to claim 3, characterized in that, The electron beam current density emitted by the electron gun is greater than or equal to 10. -9 A / cm², and less than 10 -6 A / cm², the accelerating voltage of the electron gun is 5-12V, and the distance between the electron gun and the current-limiting orifice is 4-6cm.

5. The non-contact laser-assisted sintering equipment according to claim 3, characterized in that, The electron beam of the electron beam conductive component corresponds to the grid line area on the front side of the battery cell.

6. The non-contact laser-assisted sintering equipment according to claim 5, characterized in that, The electron beam conductive component emits an electron beam to the edge grid line on the front side of the solar cell, and the distance between the outlet of the current limiting aperture and the edge grid line on the front side of the solar cell is 2-4mm.

7. The non-contact laser-assisted sintering equipment according to claim 1, characterized in that, The conductive platform is a metal conductive platform, which can be a copper platform, an aluminum platform, or a silver platform.

8. The non-contact laser-assisted sintering equipment according to claim 1, characterized in that, The worktable is either a rotary worktable with several conductive surfaces spaced apart circumferentially, or a linear transmission worktable with several conductive surfaces spaced along the transmission direction.

9. A non-contact laser-assisted sintering method, characterized in that, It operates using a non-contact laser-assisted sintering device as described in any one of claims 1-8, and includes the following operating steps: S1. Divide the front of the battery cell into a first region and a second region, and place the battery cell on a conductive platform; S2. The first region is laser-scanned, and the electron beam conductive component located on one side of the laser scanning component emits an electron beam to the second region on the front side of the cell to generate a conductive current to form a closed loop with the conductive platform in contact with the back side of the cell, so as to provide a bias voltage to perform laser-assisted sintering on the first region. S3. The second region is laser-scanned, and the electron beam conductive component located on the other side of the laser-scanning component emits an electron beam to the first region on the front side of the cell to generate a conductive current to form a closed loop with the conductive platform in contact with the back side of the cell, so as to provide a bias voltage for laser-assisted sintering of the second region.

10. The non-contact laser-assisted sintering method according to claim 9, characterized in that, In steps S2 and S3, the laser scanning element uses a 1054-1074nm infrared light source, employs a Gaussian spot, has a power matching range of 10-50W, and a scanning speed of 10-20m / s. In steps S2 and S3, the weak vacuum level of the electron beam conductive component is maintained at 0.1-1 Pa, and the electron beam current density emitted by the electron gun is greater than or equal to 10. -9 A / cm², and less than 10 -6 A / cm², the accelerating voltage of the electron gun is 5-12V, the equivalent aperture of the current limiting orifice is 0.5-2mm, the distance between the electron gun and the current limiting orifice is 4-6cm, and the distance between the outlet of the current limiting orifice and the edge grid line on the front of the cell is 2-4mm.

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