A non-contact femtosecond laser film opening device for BC battery

Abstract

This invention provides a non-contact femtosecond laser delamination device for BC (Bright Cell) silicon wafers, comprising a femtosecond laser module, a suspension support platform, and a controller. The controller is communicatively connected to both the femtosecond laser module and the suspension support platform. The controller controls the femtosecond laser module to output a femtosecond laser beam for laser delamination of the back passivation layer of the BC silicon wafer to be processed. It also controls the suspension support platform to output a nitrogen gas flow, suspending the BC silicon wafer above the platform. The nitrogen gas flow also cools the BC silicon wafer during the laser delamination process. This invention achieves non-contact suspension support of the silicon wafer while significantly reducing thermal damage to the wafer using a femtosecond laser. The continuously emitted nitrogen gas flow acts as a cooling medium, promptly removing excess heat and preventing heat accumulation that could damage the wafer. This integrated and stable process of suspended support laser delamination is achieved.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cell manufacturing technology, and in particular to a non-contact femtosecond laser film-opening device for BC cells. Background Technology

[0002] Back-contact (BC) cells have become the mainstream development route for N-type high-efficiency cells in the photovoltaic industry due to their lack of grid lines on the front, excellent bipolar passivation effect, and high conversion efficiency. The application of ultra-thin silicon wafers (≤100μm) is a key technology direction for BC cells to reduce silicon material costs and increase power density, and it is also the core exploration focus of current mass production in the industry.

[0003] However, existing laser film-opening technology for BC batteries faces many unsolvable technical problems when adapted to ultra-thin silicon wafers, which seriously restricts the industrialization process of ultra-thin and high-efficiency BC batteries.

[0004] First, traditional contact-type stage supports easily cause stress concentration, warping, and high breakage rates in silicon wafers, making it difficult to achieve a yield rate exceeding 90%, which cannot meet mass production requirements. Second, conventional nanosecond / picosecond lasers exhibit a significant heat-affected zone (HAZ) when opening the passivation layer of BC cells. Finally, the positioning accuracy of existing BC cell laser opening is insufficient. Summary of the Invention

[0005] The present invention provides a non-contact femtosecond laser film-opening device for BC batteries. By reusing a nitrogen suspension support platform as a laser processing support platform, it achieves non-contact suspension support of silicon wafers while using femtosecond lasers to significantly reduce thermal damage to silicon wafers. Furthermore, the continuously ejected nitrogen gas flow acts as a cooling medium to promptly remove residual heat and prevent heat accumulation from damaging the silicon wafer body, thus realizing integrated and stable processing of suspension support laser film opening.

[0006] This invention provides a non-contact femtosecond laser film-opening device for BC batteries, including a femtosecond laser module, a suspension support platform, and a controller; The controller is connected to the femtosecond laser module and the suspension support platform respectively. The controller is used to control the femtosecond laser module to output a femtosecond laser beam to perform laser film opening processing on the back passivation layer of the BC cell silicon wafer to be processed; and to control the suspension support platform to output a nitrogen gas flow so that the BC cell silicon wafer to be processed is suspended and supported above the suspension support platform. Nitrogen gas flow is also used to cool the silicon wafers of BC cells to be processed during the laser film-opening process.

[0007] Optionally, the controller is also used to adjust the output parameters of the femtosecond laser module and the nitrogen output of the suspension support platform; wherein the output parameters include pulse width, pulse frequency, spot diameter and laser power.

[0008] Optionally, the controller is also used to obtain the thickness and suspension gap of the BC cell silicon wafer to be processed, and to match the preset femtosecond laser module output parameter set according to the thickness and suspension gap of the BC cell silicon wafer to be processed.

[0009] Optionally, the controller is also used to obtain the material of the back passivation layer of the BC cell silicon wafer to be processed, and adjust the laser power according to the thickness of the BC cell silicon wafer to be processed and the material of the back passivation layer.

[0010] Optionally, the pulse width ranges from 100 to 200 fs, the pulse frequency ranges from 100 to 200 kHz, the spot diameter ranges from 5 to 8 μm, and the laser power ranges from 8 to 15 W.

[0011] Optionally, the controller is also used to obtain the thickness of the BC cell silicon wafer to be processed, and adjust the nitrogen output of the suspension support platform according to the thickness of the BC cell silicon wafer to be processed, so as to control the suspension gap of the BC cell silicon wafer to be processed to be maintained within a preset stable suspension gap range.

[0012] Optionally, it also includes a vision positioning module, which is used to acquire images of the surface of the silicon wafer to be processed in real time; The controller communicates with the vision positioning module and is also used to identify the feature positioning points of the BC battery silicon wafer to be processed based on the image, compare the feature positioning points with the preset feature positions, and adjust the laser scanning path of the femtosecond laser module in real time according to the comparison results. The controller is also used to acquire the orientation of the BC cell silicon wafer to be processed based on the image, and adjust the nitrogen output of the suspension support platform according to the orientation of the BC cell silicon wafer to be processed.

[0013] Optionally, the suspended support platform includes a gas flow channel, a flow regulating valve, a nitrogen inlet, and a dust removal exhaust port; the gas flow channel is evenly distributed on the surface of the suspended support platform.

[0014] Optionally, the gas flow channel aperture is 0.1–0.3 mm, the spacing between gas flow channels is 5–10 mm, and the outlet of the gas flow channel faces the BC cell silicon wafer to be processed.

[0015] Optionally, the suspension support platform is made of high-temperature resistant transparent ceramic material.

[0016] This invention provides a non-contact femtosecond laser film-opening device for BC batteries. By reusing a nitrogen-suspended support platform as a laser processing support platform, it achieves non-contact suspension support for the silicon wafer while significantly reducing thermal damage to the silicon wafer using a femtosecond laser. Furthermore, the continuously ejected nitrogen gas flow acts as a cooling medium, promptly removing excess heat and preventing heat accumulation that could damage the silicon wafer. This invention eliminates the risk of airflow disturbance at its source, achieving integrated and stable laser film-opening processing with suspension support. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a non-contact femtosecond laser film-opening device for BC batteries provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a suspension support platform provided in an embodiment of the present invention; Figure 3 This is a curve comparing the film-opening accuracy of the present invention with that of the traditional process, provided in an embodiment of the present invention. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0019] The terminology used in the embodiments of this invention is for the purpose of describing specific embodiments only and is not intended to limit the invention. It should be noted that directional terms such as "upper," "lower," "left," and "right" described in the embodiments of this invention are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this invention. Furthermore, in the context, it should be understood that when referring to an element being formed "on" or "below" another element, it can be formed not only directly on or below the other element, but also indirectly on or below it through intermediate elements. Terms such as "first," "second," etc., are used for descriptive purposes only and do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0020] The term "comprising" and its variations as used in this invention are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment".

[0021] It should be noted that the concepts of "first" and "second" mentioned in this invention are only used to distinguish the corresponding contents and are not used to limit the order or interdependence.

[0022] It should be noted that the terms "a" and "a plurality of" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0023] Figure 1 This is a schematic diagram of a non-contact femtosecond laser film-opening device for BC batteries provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the non-contact femtosecond laser decoupling device for BC batteries provided in this application is suitable for industrial mass production lines of back-contact (BC) batteries. It is used for high-precision, low-damage regional decoupling of the passivation layer on the back of a silicon wafer to expose the silicon substrate for subsequent metal electrode contact formation. This non-contact femtosecond laser decoupling device for BC batteries includes a femtosecond laser module 10, a suspension support platform 20, and a controller 30. The controller 30 is communicatively connected to the femtosecond laser module 10 and the suspension support platform 20 respectively. The controller 30 is used to control the femtosecond laser module 10 to output a femtosecond laser beam to perform laser film opening processing on the back passivation layer of the BC cell silicon wafer 1 to be processed; and to control the suspension support platform 20 to output a nitrogen gas flow so that the BC cell silicon wafer 1 to be processed is suspended and supported above the suspension support platform 20. The nitrogen gas flow is also used to cool the silicon wafer 1 of the BC cell to be processed during the laser film-opening process.

[0024] Specifically, during the processing, the controller 30 first controls the suspension support platform 20 to output a stable nitrogen gas flow, so that the BC cell silicon wafer to be processed is stably suspended above the platform at a preset height (e.g., 0.1-0.5mm) in a non-contact manner, ensuring that the silicon wafer is level and free from vibration. Subsequently, the controller 30 controls the femtosecond laser module 10 to output a femtosecond laser beam that passes through the scanning galvanometer and focusing lens, scanning and removing the passivation layer on the back of the silicon wafer according to the preset opening pattern. During the laser action, the extremely short pulse width of the femtosecond laser makes the material removal mechanism mainly based on multiphoton absorption and plasma ablation, with a very small heat diffusion distance, effectively suppressing molten material splashing and the expansion of the heat-affected zone. At the same time, the continuously ejected nitrogen gas flow not only acts as a suspension support, but also acts as a cooling medium to quickly remove the local heat and ablation products generated by the laser processing, preventing heat accumulation that could lead to microcracks in the silicon wafer or thermal damage to the characteristic positioning points of the passivation layer. Throughout the entire processing, the silicon wafer never comes into contact with any solid parts, avoiding scratches, particle contamination, or stress damage to the back of the silicon wafer caused by traditional mechanical clamping or vacuum adsorption methods.

[0025] This invention provides a non-contact femtosecond laser film-opening device for BC batteries. By reusing a nitrogen-suspended support platform as a laser processing support platform, it achieves non-contact suspension support for silicon wafers while significantly reducing thermal damage to the silicon wafers using a femtosecond laser. The continuously ejected nitrogen gas flow acts as a cooling medium, promptly removing excess heat and preventing heat accumulation that could damage the silicon wafer. Simultaneously, the extremely short pulse width of the femtosecond laser allows for material removal primarily through multiphoton absorption and plasma ablation, resulting in minimal heat diffusion distance. This effectively suppresses molten material splashing and the expansion of the heat-affected zone, thereby achieving integrated and stable laser film-opening processing with suspension support.

[0026] Optionally, the controller 30 is also used to adjust the output parameters of the femtosecond laser module 10 and the nitrogen output of the suspension support platform 20; wherein the output parameters include pulse width, pulse frequency, spot diameter and laser power.

[0027] The output parameters can be understood as the adjustable process variables of the femtosecond laser module 10, including pulse width, pulse frequency, spot diameter and laser power; the nitrogen output can be understood as the volumetric flow rate of nitrogen ejected by the suspension support platform 20 per unit time.

[0028] Specifically, the controller 30 is also used to finely adjust the output parameters of the femtosecond laser module 10 according to the passivation layer material type, film thickness, and processing quality requirements of the silicon wafer 1 to be processed (BC cell). For example, for a thicker silicon nitride layer, a larger pulse width and higher laser power can be selected to improve the removal efficiency; for a thinner silicon oxide layer, a smaller pulse width and lower power are selected to avoid damaging the silicon substrate. Simultaneously, the controller 30 is also used to control and adjust the nitrogen gas output of the suspension support platform 20 to maintain suspension stability and ensure that the silicon wafer does not drift or vibrate during laser scanning.

[0029] Optionally, the controller 30 is also used to obtain the thickness and suspension gap of the BC cell silicon wafer 1 to be processed, and to match the preset output parameter group of the femtosecond laser module 10 according to the thickness and suspension gap of the BC cell silicon wafer 1 to be processed.

[0030] The suspension gap can be understood as the vertical distance between the upper surface of the support platform 20 and the lower surface of the silicon wafer when the BC battery silicon wafer is suspended by the nitrogen gas flow; the output parameter set can be understood as a set of femtosecond laser module 10 output parameters pre-calibrated for a specific silicon wafer thickness and suspension gap.

[0031] Specifically, the controller 30 is also used to obtain the thickness of the silicon wafer 1 to be processed (BC cell) and the suspension gap under the current nitrogen gas flow before processing. Based on these two parameters, the controller 30 matches them in a preset process database and selects the corresponding set of output parameters from the femtosecond laser module 10. For example, for thicker silicon wafers or larger suspension gaps, the laser focus needs to be moved down further, so a larger spot diameter and higher laser power are selected to ensure that the passivation layer is effectively removed; conversely, for thinner silicon wafers or smaller suspension gaps (0.2 mm), the laser focus is closer to the silicon wafer surface, so a smaller spot diameter and lower laser power are selected to avoid damaging the silicon substrate.

[0032] Optionally, the controller 30 is also used to obtain the material of the back passivation layer of the BC cell silicon wafer 1 to be processed, and adjust the laser power according to the thickness of the BC cell silicon wafer 1 to be processed and the material of the back passivation layer.

[0033] The material of the back passivation layer can be understood as the type of dielectric thin film material covering the back of the BC battery silicon wafer, such as silicon oxide (SiO2) or silicon nitride (SiN). x Alumina (Al2O3) or its stacked combinations thereof.

[0034] Specifically, the controller 30 is also used to obtain the material of the back passivation layer of the silicon wafer 1 to be processed before processing. Based on the wafer thickness and the back passivation layer material, the controller 30 coordinates the adjustment of the laser power. For example, for thicker wafers or passivation layers made of difficult-to-remove silicon nitride, a higher laser power is selected to ensure complete removal; for thinner wafers or passivation layers made of silicon oxide, a lower laser power is selected to avoid over-etching and damaging the silicon substrate; for multilayer structures, the power is selected based on the total equivalent thickness and the main absorber layer material.

[0035] Optionally, the pulse width ranges from 100 to 200 fs, the pulse frequency ranges from 100 to 200 kHz, the spot diameter ranges from 5 to 8 μm, and the laser power ranges from 8 to 15 W.

[0036] Specifically, the pulse width is 100–200 fs to ensure that the ablation process is dominated by multiphoton absorption, and the heat-affected zone is less than 10% of the spot size; the pulse frequency is 100–200 kHz to achieve a balance between scanning speed and ablation efficiency, avoiding a decrease in processing efficiency due to too low a frequency or heat accumulation due to too high a frequency; the spot diameter is 5–8 μm to meet the pattern accuracy requirements of the back film opening of BC cells; and the laser power is 8–15 W to ensure that the passivation layer is completely removed in a single scan, while controlling the damage depth of the silicon substrate and not affecting the minority carrier lifetime.

[0037] Optionally, the controller 30 is also used to obtain the thickness of the BC cell silicon wafer 1 to be processed, and adjust the nitrogen output of the suspension support platform 20 according to the thickness of the BC cell silicon wafer 1 to be processed, so as to control the suspension gap of the BC cell silicon wafer 1 to be processed to be maintained within a preset stable suspension gap range.

[0038] The preset stable suspension gap range can be understood as the vertical distance range between the lower surface of the BC battery silicon wafer and the upper surface of the suspension support platform 20.

[0039] Specifically, the controller 30 is also used to obtain the thickness of the silicon wafer 1 to be processed in the BC battery before processing, and adjust the nitrogen output of the suspension support platform 20 according to the thickness, so as to control the suspension gap of the silicon wafer to be maintained within a preset stable suspension gap range.

[0040] Optionally, it also includes a vision positioning module 40, which is used to acquire images of the surface of the silicon wafer 1 to be processed in real time; The controller 30 is connected to the vision positioning module 40 and is also used to identify the feature positioning points of the BC battery silicon wafer 1 to be processed according to the image, compare the feature positioning points with the preset feature positions, and adjust the laser scanning path of the femtosecond laser module 10 in real time according to the comparison results. The controller 30 is also used to acquire the orientation of the BC cell silicon wafer 1 to be processed based on the image, and adjust the nitrogen output of the suspension support platform 20 according to the orientation of the BC cell silicon wafer 1 to be processed.

[0041] Among them, the laser scanning path can be understood as the movement trajectory of the femtosecond laser beam on the back of the silicon wafer according to the preset opening pattern; the feature positioning point can be understood as the preset geometric features on the surface of the silicon wafer used to determine the spatial position and orientation of the silicon wafer; the preset feature position can be understood as the theoretical design position of the preset geometric features on the surface of the silicon wafer used to determine the spatial position and orientation of the silicon wafer; the attitude can be understood as the spatial state of the silicon wafer in a suspended state, including the horizontal tilt and the rotation angle in the plane.

[0042] Specifically, during laser processing, the vision positioning module 40 acquires high-resolution images of the surface of the silicon wafer 1 to be processed (BC cell) in real time and transmits the images to the controller 30. The controller 30 identifies feature positioning points on the silicon wafer using image processing algorithms. The controller 30 compares the actual coordinates of the identified feature positioning points with preset feature positions to calculate translational and rotational deviations. Based on these deviations, the controller adjusts the laser scanning path of the femtosecond laser module 10 in real time. Simultaneously, the controller 30 analyzes the orientation of the silicon wafer based on the images acquired by the vision positioning module 40 to determine if the silicon wafer is tilted. If tilting is detected, the controller adjusts the nitrogen gas output of the suspension support platform 20 in the corresponding area to restore the silicon wafer to a horizontally suspended orientation.

[0043] Figure 2 This is a schematic diagram of the structure of a suspension support platform provided in an embodiment of the present invention. In an optional embodiment, the suspension support platform 20 includes a gas guide channel 21, a flow regulating valve (not shown in the figure), a nitrogen inlet (not shown in the figure), and a dust removal exhaust port 22; the gas guide channel 21 is evenly distributed on the surface of the suspension support platform 20.

[0044] Specifically, high-purity nitrogen gas enters the platform through the nitrogen inlet. After the flow rate is adjusted by the flow regulating valve 22 according to the instructions of the controller 30, it enters the gas guide channel 21. The gas guide channel 21 is evenly distributed on the surface of the suspension support platform 20, allowing the nitrogen gas to be ejected from the platform surface at a uniform flow rate and pressure. This forms a stable and uniform gas film between the suspension support platform 20 and the silicon wafer, achieving non-contact suspension of the silicon wafer. At the same time, the dust removal exhaust port 22 is set above the surface of the silicon wafer. Through the lateral or oblique low-pressure, low-flow-rate purging nozzles, surface debris generated by laser processing is cleaned. This purging airflow is independent of the suspension support airflow, and its pressure and flow rate are much lower than the nitrogen pressure at the bottom of the suspension support platform 20, ensuring that it will not impact or interfere with the stable gas film at the bottom of the silicon wafer.

[0045] Optionally, the diameter of the gas guide channel 21 is 0.1–0.3 mm, the spacing h between the gas guide channels 21 is 5–10 mm, and the outlet of the gas guide channel 21 faces the silicon wafer 1 of the BC cell to be processed.

[0046] Specifically, when the aperture is less than 0.1 mm, processing is difficult and prone to clogging, and excessive air resistance leads to insufficient levitation force. When the aperture is greater than 0.3 mm, the air output from a single aperture is too large, which can easily cause local airflow erosion or uneven air film thickness under the silicon wafer. When the spacing is less than 5 mm, the apertures are too dense, leading to increased processing costs and reduced platform mechanical strength. When the spacing is greater than 10 mm, the support blind zone between adjacent apertures is too large, and the silicon wafer may experience local collapse or vibration during laser scanning.

[0047] Optionally, the suspension support platform 20 is made of high-temperature resistant transparent ceramic material.

[0048] Specifically, high-temperature resistant transparent ceramic materials have high transmittance in the visible and near-infrared bands and can withstand the local high temperatures that may be generated during laser processing. They also have advantages such as high hardness, corrosion resistance, and low coefficient of thermal expansion.

[0049] Figure 3This is a curve comparing the film-opening accuracy of the present invention and traditional processes, provided by an embodiment of the present invention. The horizontal axis represents the hole number, indicating the 1st to 50th holes processed sequentially during the manufacturing process. The vertical axis represents the positional deviation (in μm), characterizing the degree of deviation between the actual hole position and the theoretically designed position. A smaller absolute value of the deviation indicates higher film-opening accuracy, and smaller deviation fluctuations indicate better processing stability. In the figure, the blue solid line A represents the processing deviation curve of the present application, and the red dashed line B represents the processing deviation curve of the prior art. From the overall curve performance, the positional deviation of the present application is consistently controlled within ±1 micrometer, with small and uniform fluctuations and no drastic jumps. In contrast, the deviation curve of the traditional process fluctuates drastically, with many data points exceeding the ±1 micrometer range, and some deviations even approaching the ±3 micrometer boundary, resulting in poor overall processing stability.

[0050] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A non-contact femtosecond laser film-opening device for BC batteries, characterized in that, Includes a femtosecond laser module, a suspension support platform, and a controller; The controller is communicatively connected to the femtosecond laser module and the suspension support platform. The controller is used to control the femtosecond laser module to output a femtosecond laser beam to perform laser delamination processing on the back passivation layer of the BC cell silicon wafer to be processed; and to control the suspension support platform to output a nitrogen gas flow so that the BC cell silicon wafer to be processed is suspended and supported above the suspension support platform. The nitrogen gas flow is also used to cool the silicon wafer of the BC battery to be processed during the laser film-opening process.

2. The non-contact femtosecond laser film-opening device for BC batteries according to claim 1, characterized in that, The controller is also used to adjust the output parameters of the femtosecond laser module and the nitrogen output of the suspension support platform; wherein the output parameters include pulse width, pulse frequency, spot diameter and laser power.

3. The BC battery non-contact femtosecond laser film-opening device according to claim 2, characterized in that, The controller is also used to obtain the thickness and suspension gap of the BC battery silicon wafer to be processed, and to match a preset set of femtosecond laser module output parameters according to the thickness and suspension gap of the BC battery silicon wafer to be processed.

4. The non-contact femtosecond laser film-opening device for BC batteries according to claim 3, characterized in that, The controller is also used to obtain the material of the back passivation layer of the BC battery silicon wafer to be processed, and adjust the laser power according to the thickness of the BC battery silicon wafer to be processed and the material of the back passivation layer.

5. The BC battery non-contact femtosecond laser film-opening device according to claim 2, characterized in that, The pulse width ranges from 100 to 200 fs, the pulse frequency ranges from 100 to 200 kHz, the spot diameter ranges from 5 to 8 μm, and the laser power ranges from 8 to 15 W.

6. The non-contact femtosecond laser film-opening device for BC batteries according to claim 2, characterized in that, The controller is also used to obtain the thickness of the BC battery silicon wafer to be processed, and adjust the nitrogen output of the suspension support platform according to the thickness of the BC battery silicon wafer to be processed, so as to control the suspension gap of the BC battery silicon wafer to be processed to be maintained within a preset stable suspension gap range.

7. The non-contact femtosecond laser film-opening device for BC batteries according to claim 6, characterized in that, It also includes a visual positioning module, which is used to acquire images of the surface of the silicon wafer to be processed in BC cells in real time; The controller is communicatively connected to the vision positioning module and is also used to identify the feature positioning points of the BC battery silicon wafer to be processed according to the image, compare the feature positioning points with preset feature positions, and adjust the laser scanning path of the femtosecond laser module in real time according to the comparison results. The controller is also used to acquire the orientation of the BC battery silicon wafer to be processed based on the image, and adjust the nitrogen output of the suspension support platform according to the orientation of the BC battery silicon wafer to be processed.

8. The non-contact femtosecond laser film-opening device for BC batteries according to claim 1, characterized in that, The suspended support platform includes a gas flow channel, a flow regulating valve, a nitrogen inlet, and a dust removal exhaust port; the gas flow channel is evenly distributed on the surface of the suspended support platform.

9. The BC battery non-contact femtosecond laser film-opening device according to claim 8, characterized in that, The gas flow channel has an aperture of 0.1–0.3 mm, the spacing between the gas flow channels is 5–10 mm, and the outlet of the gas flow channel faces the silicon wafer of the BC battery to be processed.

10. The non-contact femtosecond laser film-opening device for BC batteries according to claim 1, characterized in that, The suspension support platform is made of high-temperature resistant transparent ceramic material.

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