Three-waveband time-sharing common optical path laser welding spectrum detection device and method

Abstract

This invention relates to the field of laser welding spectral detection technology, and discloses a three-band time-division common optical path laser welding spectral detection device and method. In one aspect, the laser welding spectral detection device includes a time-division filtering assembly and a photodetector. The time-division filtering assembly includes a rotating shaft, a filter wheel base frame, and three filters, which are installed in three mounting slots on the filter wheel base frame. The time-division filtering assembly is used to switch the filters in the beam propagation path according to a preset time sequence, and the composite light is time-divisionally filtered to select plasma light, molten pool infrared radiation light, and laser reflected light, which are then incident on the photodetector. The laser welding spectral detection device and method of this application replaces the traditional multi-optical-path, multi-detector parallel scheme, solving the problems of poor signal synchronization, large equipment size, high cost, difficult debugging, and weak anti-interference ability in laser welding spectral detection, and achieving high-consistency time-division acquisition of three-band signals.

Description

Technical Field

[0001] This invention relates to the field of laser welding spectral detection technology, specifically to a laser welding spectral detection device and method with a three-band time-division common optical path. Background Technology

[0002] With the rapid iteration of the new energy industry, lithium batteries, as core components of electric vehicles and energy storage devices, directly determine the conductivity, safety, reliability, and lifespan of the products through their manufacturing quality. Laser welding, a core process for connecting critical components such as terminals, tabs, current collectors, and sealing nails in lithium battery production, has been widely used in the mass production of power and energy storage batteries due to its advantages of concentrated energy, small heat-affected zone, high welding precision, and ease of automation. However, it also faces stringent quality control challenges. The laser welding process generates a composite light consisting of plasma light, molten pool infrared radiation light, and laser reflection light. The stability of these composite light components directly reflects the welding quality and process stability. Even minor signal anomalies can lead to defects such as incomplete welds, spatter, insufficient penetration, and excessive spatter, severely impacting battery safety and reliability.

[0003] Among related technologies, the current mainstream spectral detection scheme adopts a multi-optical-path, multi-detector parallel acquisition method to detect three characteristic wavelength bands of light: plasma light, molten pool infrared radiation light and laser reflection light, respectively, so as to realize independent real-time monitoring of spectral signals in the welding process, which has been initially applied in industrial production lines.

[0004] However, current mainstream spectroscopic detection methods have the following significant drawbacks: ① The independent optical path parallel design requires each band to be equipped with separate optical devices such as filters, beam splitters, and detectors. The optical path layout is dispersed, the overall size of the device is large, it occupies a lot of installation space, and the multiple sets of optical devices lead to higher equipment costs, which is not conducive to low-cost mass deployment in industrial production lines.

[0005] ② Each band uses an independent detector to collect signals. Different detectors have inherent differences in response speed, sensitivity, and signal-to-noise ratio. At the same time, the optical path loss and optical path deviation are different during multi-optical path transmission, which can easily lead to timing misalignment and inconsistent amplitude of the three band signals. This makes it impossible to accurately reflect the synchronous changes of light in each characteristic band during the welding process, i.e., poor synchronization of multi-detector signals.

[0006] ③ The parallel structure for multi-optical path detection requires optical path calibration, filter matching, and detector parameter debugging for each optical path. The debugging process is cumbersome and time-consuming. During the production process, optical components are easily contaminated by smoke and oil. The cleaning and maintenance of the multi-optical path structure is difficult. Any abnormality in any optical path will affect the overall detection effect and the maintenance cost is high. In other words, the debugging of multi-optical path detection is difficult and the maintenance cost is high.

[0007] ④ When multiple optical paths are detected and acquired in parallel, external ambient light, welding spatter, and fumes can easily cause varying degrees of interference to the dispersed optical paths. The interference levels of signals in each band are inconsistent, resulting in large fluctuations in the spectral signals, which can easily trigger false alarms. The detection stability is insufficient and it is difficult to meet the quality control requirements of precision welding scenarios. In other words, the multi-optical path detection has weak anti-interference ability and insufficient detection stability. Summary of the Invention

[0008] This application provides a laser welding spectral detection device and method with three-band time-division common optical path, which replaces the traditional multi-optical-path multi-detector parallel scheme. It solves the problems of poor signal synchronization, large equipment size, high cost, difficult debugging and weak anti-interference ability in laser welding spectral detection, and realizes high consistency time-division acquisition of three-band signals.

[0009] In a first aspect, embodiments of this application provide a laser welding spectral detection device with a three-band time-division common optical path, the laser welding spectral detection device comprising a time-division filtering component and a photodetector arranged sequentially from the workpiece along the beam propagation direction; The time-division filtering assembly includes a rotating shaft, a filter wheel base frame, and three filters. The filter wheel base frame has three mounting slots and is coaxially fixed to one end of the rotating shaft. The three filters are installed in the three mounting slots one by one. The time-division filtering component is used to switch the filters in the beam propagation path according to a preset time sequence when the rotating shaft drives the filter wheel base frame to rotate, so as to select monochromatic light of three characteristic wavelength bands from the composite light generated at the welding workpiece and incident it onto the photodetector.

[0010] In conjunction with the first aspect, in one embodiment, an optical collecting lens is further disposed between the welding workpiece and the time-division filtering assembly, and the composite light is converged into a parallel beam by the optical collecting lens and enters the time-division filtering assembly.

[0011] In conjunction with the first aspect, in one embodiment, a focusing lens is further disposed between the time-division filtering component and the photodetector, wherein monochromatic light of any characteristic band among the plasma light, molten pool infrared radiation light and laser reflected light output by the time-division filtering component is focused by the focusing lens and then incident on the photodetector.

[0012] In conjunction with the first aspect, in one embodiment, the laser welding spectral detection device further includes a signal processor; the photodetector converts plasma light, molten pool infrared radiation light and laser reflected light into time-division electrical signals, which are then transmitted to the signal processor; the signal processor outputs three-band spectral detection results based on the time-division electrical signals.

[0013] In conjunction with the first aspect, in one embodiment, the three filters are a first filter, a second filter, and a third filter; the filter wheel base frame includes a circular ring structure and three radial frames, one end of the three radial frames is connected to the center of the circular ring structure, and the other end is connected to the inner side of the circular ring structure, forming three fan-shaped mounting spaces of the same size; the three fan-shaped mounting spaces are respectively embedded with the first filter, the second filter, and the third filter; The first filter is a 400-500nm narrowband filter used to filter plasma light; the second filter is an 800-1100nm narrowband filter used to filter molten pool infrared radiation light; and the third filter is a 1030-1080nm narrowband filter used to filter laser reflected light.

[0014] In conjunction with the first aspect, in one embodiment, a reflector is further disposed between the optical collecting lens and the time-division filtering assembly, the reflector being used to change the direction of the composite light.

[0015] In conjunction with the first aspect, in one embodiment, the central axis of the beam propagation path is perpendicular to the time-division filter assembly, and the central axis of the beam propagation path has a circular motion trajectory on the time-division filter assembly, the center of the circular motion trajectory coinciding with the center of the filter wheel base frame.

[0016] In conjunction with the first aspect, in one embodiment, the three filters are a first filter, a second filter, and a third filter, respectively; the signal acquisition process of the laser welding spectral detection device is a periodic cyclic sequence, and each period T is divided into a first acquisition period T1, a second acquisition period T2, and a third acquisition period T3, wherein T1=T2=T3 and T=T1+T2+T3; During the first acquisition period T1, the first filter enters the optical path, and the photodetector acquires the 400-500nm plasma light signal; during the second acquisition period T2, the second filter enters the optical path, and the photodetector acquires the 800-1100nm molten pool infrared light signal; during the third acquisition period T3, the third filter enters the optical path, and the photodetector acquires the 1030-1080nm laser reflection light signal; the signal processor groups the electrical signals according to the timestamp, assigning the signal from time T1 to the plasma channel, the signal from time T2 to the molten pool infrared channel, and the signal from time T3 to the laser reflection channel.

[0017] Secondly, embodiments of this application provide a spectral detection method for the aforementioned laser welding spectral detection device, comprising the following steps: When the laser welding spectral detection device is powered on, the rotating shaft drives the filter wheel base frame to rotate at a uniform speed. After laser welding begins, the composite light generated at the workpiece enters the time-division filtering component; The time-division filtering component switches filters according to a preset time sequence, sequentially outputting plasma light, molten pool infrared radiation light, and laser reflected light, which are then incident on the photodetector.

[0018] In conjunction with the second aspect, in one embodiment, the three filters are a first filter, a second filter, and a third filter, respectively; the laser welding spectral detection device further includes a signal processor, and the signal acquisition process of the laser welding spectral detection device is a periodic cyclical sequence, with each period T being divided into a first acquisition period T1, a second acquisition period T2, and a third acquisition period T3, wherein T1=T2=T3 and T=T1+T2+T3; The time-division filtering component switches filters according to a preset time sequence, sequentially outputting plasma light, molten pool infrared radiation light, and laser reflected light, which are then incident on the photodetector. It includes: During the first acquisition period T1, the first filter enters the optical path, and the photodetector acquires the 400~500nm plasma light signal; during the second acquisition period T2, the second filter enters the optical path, and the photodetector acquires the 800~1100nm molten pool infrared light signal; during the third acquisition period T3, the third filter enters the optical path, and the photodetector acquires the 1030~1080nm laser reflected light signal. The photodetector converts plasma optical signals, molten pool infrared optical signals, and laser reflected optical signals into time-division electrical signals, which are then transmitted to the signal processor. After the light enters the photodetector, it also includes: The signal processor groups the electrical signals according to timestamps, assigning the signal in time period T1 to the plasma channel, the signal in time period T2 to the molten pool infrared channel, and the signal in time period T3 to the laser reflection channel.

[0019] The beneficial effects of the technical solutions provided in this application include: 1. The three-band time-division common optical path laser welding spectral detection device of this application, through a three-band time-division common optical path multiplexing architecture, directs the composite light generated at the welding workpiece to a time-division filtering component. The time-division filtering component switches the filters in the beam propagation path according to a preset time sequence, thereby allowing the composite light to be filtered by three filters in a time-division manner to separate plasma light, molten pool infrared radiation light, and laser reflection light, which are then directed to a photodetector. The three characteristic band light signals of plasma, molten pool infrared, and laser reflection are collected in a time-division manner through the same optical path and the same detector. From the hardware structure level, this simplifies the optical path design, reduces the device size, and lowers the equipment cost, solving the technical problems of dispersed optical path layout, large overall device size, and high equipment cost in current mainstream spectral detection schemes. At the same time, it uses only the same optical path and one photodetector. The detector eliminates the inherent differences in response speed, sensitivity, and signal-to-noise ratio among different detectors, and also avoids the problems of optical path loss and optical path deviation during multi-path transmission that lead to timing misalignment and amplitude inconsistency among the three-band optical signals, ensuring the synchronization and consistency of the three-band optical signals. Furthermore, by using only a single optical path and a single photodetector, the technical problems of high debugging difficulty and high maintenance cost in current mainstream spectral detection schemes involving multiple optical paths are solved. Finally, by using only a single optical path and a single photodetector, the technical problems of weak anti-interference capability and insufficient detection stability in multi-optical path detection are solved. The laser welding spectral detection device with three-band time-division common optical path proposed in this application improves the stability and accuracy of spectral detection, meeting the demand for high-precision, low-cost online detection solutions in large-scale laser welding production.

[0020] 2. The three-band time-division common optical path laser welding spectral detection device of this application realizes continuous time-division acquisition of three-band signals in a cyclical manner. Each cycle T is divided into a first acquisition period T1, a second acquisition period T2, and a third acquisition period T3. In the first acquisition period T1, the first filter enters the optical path, and the photodetector acquires the 400~500nm plasma light signal. In the second acquisition period T2, the second filter enters the optical path, and the photodetector acquires the 800~1100nm molten pool infrared light signal. In the third acquisition period T3, the third filter enters the optical path, and the photodetector acquires the 1030~1080nm laser reflection light signal. At the same time, the signal processor groups the electrical signals according to the timestamp, assigning the T1 period signal to the plasma channel, the T2 period signal to the molten pool infrared channel, and the T3 period signal to the laser reflection channel, thus completing the separation and reconstruction of the three-band signals. It can efficiently complete the separation and detection of monochromatic light in three characteristic bands, generate three-band spectral data, and output the detection results, realizing online monitoring of welding process quality. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A schematic diagram of the laser welding spectral detection device provided in the embodiments of this application; Figure 2 A schematic diagram of the time-division filtering component of the laser welding spectral detection device provided in the embodiments of this application; Figure 3 A schematic flowchart of the spectral detection method provided in the embodiments of this application; Reference numerals: 1. Welded workpiece; 2. Optical collecting lens; 3. Time-division filtering assembly; 4. Focusing lens; 5. Photodetector; 6. Signal processor; 31. Rotating shaft; 32. Filter wheel base frame; 33. First filter; 34. Second filter; 35. Third filter. Detailed Implementation

[0023] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0024] This application provides a laser welding spectral detection device and method with three-band time-division common optical path, which replaces the traditional multi-optical-path multi-detector parallel scheme. It solves the problems of poor signal synchronization, large equipment size, high cost, difficult debugging and weak anti-interference ability in laser welding spectral detection, and realizes high consistency time-division acquisition of three-band signals.

[0025] This application addresses four technical problems of current mainstream spectral detection schemes: ① dispersed optical path layout, large overall device size and high cost, ② poor synchronization and insufficient consistency of multi-detector signals, ③ high debugging difficulty and high maintenance cost of multi-optical path detection, and ④ weak anti-interference ability and insufficient detection stability of multi-optical path detection.

[0026] Firstly, such as Figure 1 and Figure 2As shown, this application discloses an embodiment of a laser welding spectral detection device with a three-band time-division common optical path. The laser welding spectral detection device includes a time-division filter component 3 and a photodetector 5 arranged sequentially from the workpiece 1 along the beam propagation direction.

[0027] The time-division filtering assembly 3 includes a rotating shaft 31, a filter wheel base frame 32, and three filters. The filter wheel base frame 32 has three mounting slots and is coaxially fixed to one end of the rotating shaft 31. The three filters are installed in the three mounting slots. When the rotating shaft 31 rotates, it drives the filter wheel base frame 32 to rotate, which in turn drives the three filters, thus changing the filter that cuts into the beam propagation path.

[0028] The time-division filtering component 3 is used to switch the filters in the beam propagation path according to a preset time sequence when the rotating shaft 31 drives the filter wheel base frame 32 to rotate. It selects monochromatic light of three characteristic bands from the composite light (i.e., plasma light, molten pool infrared radiation light and laser reflection light mixed together) generated at the welding workpiece 1. The monochromatic light of the three characteristic bands represents plasma light, molten pool infrared radiation light and laser reflection light. The plasma light, molten pool infrared radiation light and laser reflection light are incident on the photodetector 5 in a time-division manner.

[0029] Specifically, the filter wheel base frame 32 has a circular structure, and one end of the rotating shaft 31 is vertically fixed to the circular part of the filter wheel base frame 32. When the rotating shaft 31 rotates, it drives the filter wheel base frame 32 to rotate.

[0030] Specifically, the laser welding process generates a composite light consisting of plasma light, molten pool infrared radiation light, and laser reflected light, which propagates along the beam propagation direction.

[0031] Specifically, the preset timing is related to the rotational speed of the rotating shaft 31 and the arc path that the composite light is perpendicularly incident on each filter and travels during rotation.

[0032] The three-band time-division common optical path laser welding spectral detection device of this application, through a three-band time-division common optical path multiplexing architecture, directs the composite light generated at the welding workpiece 1 onto the time-division filter component 3. The time-division filter component 3 switches the filters in the beam propagation path according to a preset time sequence, thereby allowing the composite light to be filtered by the three filters in a time-division manner to separate plasma light, molten pool infrared radiation light, and laser reflection light, which are then directed to the photodetector 5. The three characteristic band optical signals of plasma, molten pool infrared, and laser reflection are collected in a time-division manner through the same optical path and the same detector, simplifying the optical path design, reducing the device size, and lowering the equipment cost from the hardware structure level. This solves the technical problems of the current mainstream spectral detection schemes, such as dispersed optical path layout, large overall device size, and high equipment cost. At the same time, it uses only the same optical path and one photodetector. The detector 5 eliminates the inherent differences in response speed, sensitivity, and signal-to-noise ratio among different detectors, and also avoids the problems of optical path loss and optical path deviation during multi-optical path transmission that lead to timing misalignment and amplitude inconsistency among the three optical bands, ensuring the synchronization and consistency of the three optical bands. Furthermore, by using only one optical path and one photodetector 5, it solves the technical problems of high debugging difficulty and high maintenance cost in current mainstream spectral detection schemes involving multiple optical paths. Finally, by using only one optical path and one photodetector 5, it solves the technical problems of weak anti-interference capability and insufficient detection stability in multi-optical path detection. The laser welding spectral detection device with three-band time-division common optical path proposed in this application improves the stability and accuracy of spectral detection, meeting the demand for high-precision, low-cost online detection solutions in large-scale laser welding production.

[0033] Furthermore, in one embodiment, an optical collecting lens 2 is also provided between the welding workpiece 1 and the time-division filtering assembly 3. The composite light generated at the welding workpiece 1 is converged into a parallel beam by the optical collecting lens 2 and enters the time-division filtering assembly 3.

[0034] Specifically, the axis of the optical collecting lens 2 is perpendicular to the welding workpiece 1, and the welding workpiece 1 is located directly below the optical collecting lens 2, ensuring that the composite light is incident perpendicularly onto the optical collecting lens 2, thereby reducing optical path loss and signal deviation.

[0035] Furthermore, in one embodiment, a focusing lens 4 is also provided between the time-division filtering component 3 and the photodetector 5. Monochromatic light of any characteristic band among the plasma light, molten pool infrared radiation light and laser reflection light output by the time-division filtering component 3 is focused by the focusing lens 4 and then incident on the photodetector 5.

[0036] Specifically, the time-division filter component 3 outputs monochromatic light with a single characteristic wavelength band, namely, one of plasma light, molten pool infrared radiation light, or laser reflected light.

[0037] Specifically, the optical collecting lens 2, focusing lens 4, and photodetector 5 are arranged coaxially along the same horizontal optical path, forming a coaxial integrated structure that is compact and eliminates the need for a multi-optical-path distributed layout. The time-division filtering component 3 is set off-center.

[0038] The three-band time-division common optical path laser welding spectral detection device of this application embodiment has an optical collecting lens 2, a focusing lens 4 and a photodetector 5 arranged coaxially along the same horizontal optical path. It has a compact structure, does not require a multi-optical path distributed layout, and is highly practical.

[0039] Furthermore, in one embodiment, the laser welding spectral detection device also includes a signal processor 6.

[0040] The photodetector 5 converts optical signals such as plasma light, molten pool infrared radiation light and laser reflection light into time-division electrical signals and transmits them to the signal processor 6.

[0041] The signal processor 6 is based on time-division electrical signals. It performs time-series separation, data calibration and feature analysis on the time-division electrical signals, and outputs three-band spectral detection results to realize online monitoring of spectral signals in the laser welding process.

[0042] The three-band time-division common optical path laser welding spectral detection device of this application uses a photodetector 5 to convert optical signals such as plasma light, molten pool infrared radiation light, and laser reflected light into time-division electrical signals. The signal processor 6 outputs three-band spectral detection results based on time-division electrical signals to achieve accurate, automatic, and long-term monitoring.

[0043] Furthermore, in one embodiment, the three filters are a first filter 33, a second filter 34, and a third filter 35. The filter wheel base frame 32 includes a circular ring structure and three radial brackets. One end of the three radial brackets converges and connects to the center of the circular ring structure, and the other end connects to the inner side of the circular ring structure, forming three fan-shaped mounting spaces of the same size. The first filter 33, the second filter 34, and the third filter 35 are respectively embedded in the three fan-shaped mounting spaces.

[0044] The first filter 33 is a 400~500nm narrowband filter used to filter plasma light; the second filter 34 is an 800~1100nm narrowband filter used to filter molten pool infrared radiation light; and the third filter 35 is a 1030~1080nm narrowband filter used to filter laser reflected light.

[0045] In actual operation, the rotating shaft 31 drives the filter wheel base frame 32 to rotate at a constant speed, so that the first filter 33, the second filter 34, and the third filter 35 are sequentially inserted into the beam propagation path, and plasma light, molten pool infrared radiation light and laser reflected light are selected in a time-division manner to achieve time-division output of light in three characteristic wavelength bands.

[0046] Furthermore, in one embodiment, a reflector is also provided between the optical collecting lens 2 and the time-division filtering assembly 3, and the reflector is used to change the direction of the composite light.

[0047] Furthermore, the central axis of the beam propagation path is perpendicular to the time-division filter assembly 3, and the central axis of the beam propagation path has a circular motion trajectory on the time-division filter assembly 3, the center of the circular motion trajectory coincides with the center of the filter wheel base frame 32.

[0048] Furthermore, the filter switching frequency can be adjusted according to the welding speed, with a preferred switching frequency of 100~500Hz to ensure the real-time and continuous acquisition of signals in each band.

[0049] Furthermore, in one embodiment, the three filters are a first filter 33, a second filter 34, and a third filter 35, respectively. The signal acquisition process of the laser welding spectral detection device is a periodic cyclic sequence. Each period T is divided into the first acquisition period T1, the second acquisition period T2, and the third acquisition period T3. The three periods are of equal length, that is, T1=T2=T3, and the period T=T1+T2+T3.

[0050] During the first acquisition period T1, the first filter 33 enters the optical path, and the photodetector 5 acquires the 400~500nm plasma light signal; during the second acquisition period T2, the second filter 34 enters the optical path, and the photodetector 5 acquires the 800~1100nm molten pool infrared light signal; during the third acquisition period T3, the third filter 35 enters the optical path, and the photodetector 5 acquires the 1030~1080nm laser reflected light signal.

[0051] The signal processor 6 groups the electrical signals according to the timestamp, assigning the signal in time period T1 to the plasma channel, the signal in time period T2 to the molten pool infrared channel, and the signal in time period T3 to the laser reflection channel, thus completing the separation and reconstruction of the three-band signals and ensuring that the three signals are synchronized in time and have the same data source.

[0052] The three-band time-division common optical path laser welding spectral detection device of this application realizes continuous time-division acquisition of three-band signals in a cyclical manner. Each cycle T is further divided into a first acquisition period T1, a second acquisition period T2, and a third acquisition period T3. In the first acquisition period T1, the first filter 33 enters the optical path, and the photodetector 5 acquires the 400~500nm plasma light signal; in the second acquisition period T2, the second filter 34 enters the optical path, and the photodetector 5 acquires the 800~1100nm molten pool infrared light signal; During the third acquisition period T3, the third filter 35 enters the optical path, and the photodetector 5 acquires the 1030~1080nm laser reflected light signal. At the same time, the signal processor 6 groups the electrical signals according to the timestamp, assigning the signal of time period T1 to the plasma channel, the signal of time period T2 to the molten pool infrared channel, and the signal of time period T3 to the laser reflection channel, thus completing the separation and reconstruction of the three-band signals. This enables efficient separation and detection of monochromatic light in three characteristic bands, generating three-band spectral data and outputting the detection results, thereby realizing online monitoring of welding process quality.

[0053] Secondly, such as Figure 3 As shown, this application also discloses an embodiment of a spectral detection method based on the above-mentioned three-band time-division common optical path laser welding spectral detection device. The spectral detection method includes the following steps: When the laser welding spectral detection device is powered on, the rotating shaft 31 drives the filter wheel base frame 32 to rotate at a uniform speed. After laser welding begins, the composite light generated at point 1 of the workpiece enters the time-division filter assembly 3; The time-division filtering component 3 switches filters according to a preset time sequence, and outputs plasma light, molten pool infrared radiation light and laser reflected light in sequence, which are then incident on the photodetector 5.

[0054] Furthermore, in one embodiment, the three filters are a first filter 33, a second filter 34, and a third filter 35. The laser welding spectral detection device also includes a signal processor 6. The photodetector 5 converts the plasma light, the molten pool infrared radiation light, and the laser reflected light into a time-division electrical signal, which is then transmitted to the signal processor 6. The signal acquisition process of the laser welding spectral detection device is a periodic cyclic sequence, with each period T divided into a first acquisition period T1, a second acquisition period T2, and a third acquisition period T3, where T1=T2=T3 and T=T1+T2+T3.

[0055] The time-division filtering component 3 switches filters according to a preset time sequence, sequentially outputting plasma light, molten pool infrared radiation light, and laser reflected light, which are then incident on the photodetector 5, including: During the first acquisition period T1, the first filter 33 enters the optical path, and the photodetector 5 acquires the 400~500nm plasma light signal; during the second acquisition period T2, the second filter 34 enters the optical path, and the photodetector 5 acquires the 800~1100nm molten pool infrared light signal; during the third acquisition period T3, the third filter 35 enters the optical path, and the photodetector 5 acquires the 1030~1080nm laser reflected light signal. The photodetector 5 converts the plasma optical signal, the molten pool infrared optical signal, and the laser reflected optical signal into a time-division electrical signal, which is then transmitted to the signal processor 6. After incident on photodetector 5, it also includes: The signal processor 6 groups the electrical signals according to the timestamp, classifying the signal in time period T1 into the plasma channel, the signal in time period T2 into the molten pool infrared channel, and the signal in time period T3 into the laser reflection channel.

[0056] Furthermore, the laser welding spectral detection device includes an optical collecting lens 2 and a focusing lens 4.

[0057] The spectral detection method of the three-band time-division common optical path laser welding spectral detection device of this application realizes the time-division acquisition of three-band spectral signals by using a single optical path, a single detector and a time-division filter component. This simplifies the optical path structure, reduces equipment costs, and at the same time ensures the synchronization and consistency of the three-band signals, improving the stability and accuracy of spectral detection. It is suitable for precision laser welding scenarios such as lithium battery and automobile manufacturing.

[0058] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0059] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0060] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A laser welding spectral detection device with a three-band time-division common optical path, characterized in that: The laser welding spectral detection device includes a time-division filter assembly (3) and a photodetector (5) arranged sequentially from the welded workpiece (1) along the beam propagation direction. The time-division filtering assembly (3) includes a rotating shaft (31), a filter wheel base frame (32), and three filters. The filter wheel base frame (32) is provided with three mounting slots and is coaxially fixed at one end of the rotating shaft (31). The three filters are installed in the three mounting slots one by one. The time-division filtering component (3) is used to switch the filters in the beam propagation path according to a preset time sequence when the rotating shaft (31) drives the filter wheel base frame (32) to rotate. It selects monochromatic light of three characteristic bands from the composite light generated at the welding workpiece (1) and incident it onto the photodetector (5).

2. The laser welding spectral detection device with three-band time-division common optical path as described in claim 1, characterized in that: An optical collecting lens (2) is also provided between the welding workpiece (1) and the time-division filter assembly (3). The composite light is converged into a parallel beam by the optical collecting lens (2) and enters the time-division filter assembly (3).

3. The laser welding spectral detection device with three-band time-division common optical path as described in claim 1, characterized in that: A focusing lens (4) is also provided between the time-division filtering component (3) and the photodetector (5). Monochromatic light of any characteristic band among plasma light, molten pool infrared radiation light and laser reflection light output by the time-division filtering component (3) is focused by the focusing lens (4) and then incident on the photodetector (5).

4. The laser welding spectral detection device with three-band time-division common optical path as described in claim 1, characterized in that: The laser welding spectral detection device also includes a signal processor (6). The photodetector (5) converts plasma light, molten pool infrared radiation light and laser reflected light into time-division electrical signals and transmits them to the signal processor (6). The signal processor (6) outputs the three-band spectral detection results based on the time-division electrical signal.

5. The laser welding spectral detection device with three-band time-division common optical path as described in claim 1, characterized in that: The three filters are a first filter (33), a second filter (34), and a third filter (35). The filter wheel base frame (32) includes a circular ring structure and three radial frames. One end of the three radial frames is connected to the center of the circular ring structure, and the other end is connected to the inner side of the circular ring structure, forming three fan-shaped mounting spaces of the same size. The first filter (33), the second filter (34), and the third filter (35) are respectively embedded in the three fan-shaped mounting spaces. The first filter (33) is a 400~500nm narrowband filter used to filter plasma light; the second filter (34) is an 800~1100nm narrowband filter used to filter molten pool infrared radiation light; and the third filter (35) is a 1030~1080nm narrowband filter used to filter laser reflected light.

6. The laser welding spectral detection device with three-band time-division common optical path as described in claim 2, characterized in that: A reflector is also provided between the optical collecting lens (2) and the time-division filtering assembly (3), and the reflector is used to change the direction of the composite light.

7. The laser welding spectral detection device with three-band time-division common optical path as described in claim 1, characterized in that: The central axis of the beam propagation path is perpendicular to the time-division filter assembly (3), and the central axis of the beam propagation path has a circular motion trajectory on the time-division filter assembly (3), the center of the circular motion trajectory coincides with the center of the filter wheel base frame (32).

8. The laser welding spectral detection device with three-band time-division common optical path as described in claim 4, characterized in that: The three filters are the first filter (33), the second filter (34), and the third filter (35), respectively. The signal acquisition process of the laser welding spectral detection device is a periodic cyclic sequence, and each period T is divided into the first acquisition period T1, the second acquisition period T2, and the third acquisition period T3, where T1=T2=T3 and T=T1+T2+T3. During the first acquisition period T1, the first filter (33) enters the optical path, and the photodetector (5) acquires 400~500nm plasma light signals; during the second acquisition period T2, the second filter (34) enters the optical path, and the photodetector (5) acquires 800~1100nm molten pool infrared light signals; during the third acquisition period T3, the third filter (35) enters the optical path, and the photodetector (5) acquires 1030~1080nm laser reflection light signals; the signal processor (6) groups the electrical signals according to the timestamp, assigning the T1 period signal to the plasma channel, the T2 period signal to the molten pool infrared channel, and the T3 period signal to the laser reflection channel.

9. A spectral detection method based on the laser welding spectral detection device of claim 1, characterized in that, Includes the following steps: When the laser welding spectral detection device is powered on, the rotating shaft (31) drives the filter wheel base frame (32) to rotate at a constant speed; After laser welding begins, the composite light generated at the workpiece (1) enters the time-division filter assembly (3). The time-division filtering component (3) switches filters according to a preset time sequence, and outputs plasma light, molten pool infrared radiation light and laser reflection light in sequence, which are then incident on the photodetector (5).

10. The spectral detection method of the laser welding spectral detection device as described in claim 9, characterized in that: The three filters are a first filter (33), a second filter (34), and a third filter (35); the laser welding spectral detection device also includes a signal processor (6), and the signal acquisition process of the laser welding spectral detection device is a periodic cyclic sequence, with each period T divided into a first acquisition period T1, a second acquisition period T2, and a third acquisition period T3, where T1=T2=T3 and T=T1+T2+T3; The time-division filtering component (3) switches filters according to a preset time sequence, sequentially outputting plasma light, molten pool infrared radiation light, and laser reflected light, which are incident on the photodetector (5), including: During the first acquisition period T1, the first filter (33) enters the optical path, and the photodetector (5) acquires 400~500nm plasma light signals; during the second acquisition period T2, the second filter (34) enters the optical path, and the photodetector (5) acquires 800~1100nm molten pool infrared light signals; during the third acquisition period T3, the third filter (35) enters the optical path, and the photodetector (5) acquires 1030~1080nm laser reflected light signals; The photodetector (5) converts the plasma light signal, the molten pool infrared light signal and the laser reflection light signal into a time-division electrical signal and transmits it to the signal processor (6). After the incident light reaches the photodetector (5), it also includes: The signal processor (6) groups the electrical signals according to the timestamp, classifying the signal in time period T1 as the plasma channel, the signal in time period T2 as the molten pool infrared channel, and the signal in time period T3 as the laser reflection channel.

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