An intelligent laser welding system and welding method

Abstract

The application discloses an intelligent laser welding system and a welding method, and belongs to the technical field of laser welding.The system comprises a laser processing device, an OCT detection device, a processing head, a moving device and a main controller; measurement light emitted by the OCT detection device and welding laser emitted by the laser processing device are coaxially emitted to a workpiece through the processing head, so that real-time detection of welding penetration depth is realized; the penetration depth data is analyzed through a logic control system; the penetration depth data and a preset threshold value are compared in real time; the coordinates of a region with insufficient penetration depth are marked; a repair welding instruction is automatically generated; a repair welding program is called; repair welding operation is realized in situ under the condition of no shutdown; and production efficiency and product qualification rate are improved.

Description

Technical Field

[0001] This invention belongs to the field of laser welding technology, specifically relating to an intelligent laser welding system and welding method. Background Technology

[0002] The welding of busbars (connector pieces) in battery modules is a core process in lithium battery manufacturing, which directly affects the performance, safety, lifespan, and manufacturing cost of battery modules / packs.

[0003] Busbar welding often involves manual inspection to assess weld quality. However, manual inspection is a destructive test. Even if the inspected weld is initially deemed acceptable, its long-term reliability and current-carrying capacity may decrease due to plastic deformation or internal damage. Such batteries or modules cannot be shipped and are typically treated as samples or scrapped. Furthermore, manual inspection is usually only used for sampling inspection or process verification and cannot achieve 100% weld monitoring. If defective products from uninspected batches enter the market, it could lead to catastrophic consequences, such as vehicle / equipment fires and explosions, sudden power outages and breakdowns, permanent damage to battery packs, significant capacity reduction, and deterioration of cell consistency.

[0004] In addition, although there are existing welding systems that can perform online inspection of weld joints, if defects are found and rework is required, the machine needs to be stopped and the workpiece removed. This is inefficient and has poor positioning accuracy, which affects the normal operation of production. Summary of the Invention

[0005] In response to one or more of the above-mentioned defects or improvement needs of the existing technology, the present invention provides an intelligent laser welding system and welding method, which can solve the problem of insufficient penetration depth caused by gaps and contamination in traditional welding, requiring secondary positioning and rework at the welding station, and realize real-time welding repair at the welding station.

[0006] To achieve the above objectives, one aspect of the present invention provides an intelligent laser welding system and welding method, which includes a laser processing apparatus, an OCT detection apparatus, a processing head, a moving device, and a main controller; The output ends of both the laser processing device and the OCT detection device are located on the processing head, so that the welding laser emitted by the laser processing device and the measuring light emitted by the OCT detection device are coaxially emitted onto the workpiece through the processing head; and the measuring light returns to the OCT detection device along the original path after contacting the workpiece, so as to detect the weld penetration depth. The processing head is mounted on the moving device so that the moving device can drive the processing head to move relative to the workpiece; The main controller is connected to the laser processing device, the OCT detection device, and the mobile device; the main controller includes a logic control system, which includes a penetration depth analysis module, a defect location module, and a parameter optimization module. The penetration depth analysis module performs real-time analysis and comparison between the penetration depth data fed back by the OCT detection device and a preset threshold to determine the area with insufficient penetration depth and the type of defect, and generates a repair welding instruction; the defect location module is used to mark the coordinates of the area with insufficient penetration depth; the parameter optimization module includes a mapping relationship library between defect types and repair welding parameters, so as to automatically call the repair welding program according to the defect characteristics.

[0007] As a further improvement of the present invention, the defect type includes gap defects, and the welding parameters for repairing the gap defects include at least one of the following: laser power increase of 0-30%, welding speed decrease of 0-50%, defocusing amount adjustment, and weld size increase of 0-2mm.

[0008] As a further improvement of the present invention, the gap defect and the laser power for repair welding have the following relationship: Repair welding laser power = normal laser power + k × gap size; Where K is a coefficient.

[0009] As a further improvement of the present invention, the processing head includes a first beam splitter, a second beam splitter, a galvanometer assembly, and a field lens; The first beam splitter is configured to correspond to the laser processing device to reflect the welding laser to the galvanometer assembly; the second beam splitter is configured to correspond to the OCT detection device to reflect the measurement light to be coaxial with the welding laser and incident on the galvanometer assembly. The galvanometer assembly is used to adjust the output direction of the welding laser and the measuring light; The field lens is used to focus the welding laser and the measuring light and then emit them onto the workpiece.

[0010] As a further improvement of the present invention, the galvanometer assembly includes an X-mirror and a Y-mirror arranged sequentially along the beam output direction. The X-mirror is used to deflect the beam in the X direction, and the Y-mirror is used to deflect the beam in the Y direction.

[0011] As a further improvement of the present invention, the processing head also includes a field lens protection lens, which is disposed at the output end of the processing head for protecting the field lens.

[0012] As a further improvement of the present invention, the distance between the measuring light spot and the welding laser spot is less than 0.5 mm.

[0013] As a further improvement of the present invention, the mobile device is a multi-axis robot or a three-axis motion platform.

[0014] As a further improvement of the present invention, the laser processing apparatus includes a laser, a transmission optical fiber, and a chiller; one end of the transmission optical fiber is connected to the laser, and the other end is connected to the processing head to input the welding laser emitted by the laser to the processing head; the chiller is used to cool the laser.

[0015] Another aspect of the present invention provides an intelligent laser welding method, which utilizes the aforementioned intelligent laser welding system for welding, characterized by comprising the following steps: (1) The laser processing device emits a welding laser through the processing head to perform laser welding on the workpiece weld; at the same time, the OCT detection device emits a measuring light through the processing head to obtain the weld penetration data in real time and transmits the penetration data to the main controller. (2) The penetration depth analysis module analyzes the penetration depth data. If an area with insufficient penetration depth is identified, the penetration depth analysis module confirms the defect type and generates a repair welding instruction. The defect location module marks the coordinates of the area with insufficient penetration depth. (3) After the welding path is completed, the main controller controls the moving device to move the processing head above the defective weld according to the coordinates of the insufficient penetration area marked by the defect positioning module, and the repair weld covers the area within 1 mm around the defective weld. (4) The parameter optimization module automatically calls the repair welding parameters according to the defect characteristics. The main controller controls the laser processing device and the moving device to perform repair welding operation according to the repair welding parameters. The OCT detection device detects the weld penetration depth of the repair weld in real time. (5) If the weld penetration depth of the repair weld is qualified, the welding of the workpiece is completed; if the weld penetration depth of the repair weld is not qualified, repeat steps (2) to (4) until the weld penetration depth of the repair weld is qualified, and the laser welding of the workpiece is completed.

[0016] The aforementioned improved technical features can be combined with each other as long as they do not conflict with each other.

[0017] In summary, the beneficial effects of the above-described technical solutions conceived by this invention compared with the prior art include: (1) The intelligent laser welding system and welding method of the present invention achieve real-time detection of welding penetration by coaxially transmitting the measuring light emitted by the OCT detection device and the welding laser emitted by the laser processing device onto the workpiece through the processing head. The system analyzes the penetration data through the logic control system, compares the penetration data with the preset threshold in real time, marks the coordinates of the area with insufficient penetration, and automatically generates a repair welding command and calls the repair welding program to realize the in-situ repair welding operation without stopping the machine, thereby improving production efficiency and product qualification rate. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the overall structure of the intelligent laser welding system in an embodiment of the present invention; Figure 2 This is a schematic diagram of the internal structure of the processing head in an embodiment of the present invention; Figure 3 This is a flowchart of the intelligent laser welding method in an embodiment of the present invention; In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1. Processing head; 101. First beam splitter; 102. Second beam splitter; 103. X-ray galvanometer; 104. Y-ray galvanometer; 105. Field lens; 106. Field lens protective lens; 2. Moving device; 3. Laser; 301. Welding laser; 4. Chiller; 5. Transmission optical fiber; 6. OCT detection device; 601. Measuring light; 7. Main controller; 8. Workpiece; 9. Platform. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0021] In the description of this invention, it should be understood that, unless otherwise expressly specified and limited, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and are not intended to 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 invention.

[0022] Furthermore, unless otherwise expressly specified and limited, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly and specifically limited.

[0023] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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 of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0025] Example: Please see Figures 1-3 The intelligent laser welding system in a preferred embodiment of the present invention includes a laser processing device, an OCT detection device 6, a processing head 1, a moving device 2, and a main controller 7. The laser processing device emits a welding laser 301, the OCT detection device 6 emits a measuring light 601, and the processing head 1 coaxially emits the welding laser 301 and the measuring light 601 onto the workpiece 8 located on the platform 9. The welding laser 301 is used to weld the weld seam of the workpiece 8, and the measuring light 601 is used to measure the weld penetration. At the same time, the main controller 7 controls each device to perform in-situ repair welding on areas with insufficient penetration.

[0026] Specifically, such as Figure 1 As shown, the laser processing apparatus in the preferred embodiment includes a laser 3 and a transmission optical fiber 5, wherein one end of the transmission optical fiber 5 is connected to the laser 3 and the other end is connected to the processing head 1, so as to input the welding laser 301 emitted by the laser 3 into the processing head 1 through the transmission optical fiber 5.

[0027] Preferably, a chiller 4 is also provided for the laser 3 to perform circulating water cooling and temperature control on the laser 3, so as to ensure the laser output quality of the laser 3 and improve the processing accuracy and processing efficiency.

[0028] Furthermore, in the preferred embodiment, the output end of the OCT detection device 6 is also connected to the processing head 1 so that the measuring light 601 emitted by the OCT detection device 6 and the welding laser 301 are coaxially incident on the workpiece 8 through the processing head 1, and after contacting the workpiece 8, it returns to the OCT detection device 6 along the original path to measure the welding penetration of the workpiece 8.

[0029] Furthermore, such as Figure 2 The processing head 1 in the preferred embodiment shown includes a first beam splitter 101, a second beam splitter 102, a galvanometer assembly, and a field lens 105. The first beam splitter 101 is disposed at the output end of the transmission fiber 5 to reflect the welding laser 301 to the galvanometer assembly. The second beam splitter 102 is disposed at the output end of the OCT detection device 6 to reflect the measurement light 601 to be coaxial with the welding laser 301 and to reflect the measurement light 601 to the galvanometer assembly.

[0030] Accordingly, the galvanometer assembly is used to adjust the output direction of the welding laser 301 and the measuring light 601 to cooperate with the moving device 2 to output the beam to the point to be welded.

[0031] Preferably, the galvanometer assembly includes an X-mirror 103 and a Y-mirror 104 arranged sequentially along the beam output direction, wherein the X-mirror 103 is used to deflect the beam in the X direction and the Y-mirror 104 is used to deflect the beam in the Y direction.

[0032] Preferably, in actual setup, the distance between the measuring light spot 601 and the welding laser spot 301 can be less than 0.5mm by mechanically modulating the optical path or by using a three-point calibration method, so that the coaxiality error between the detection optical path and the laser processing optical path is ≤0.05°, ensuring the accuracy and precision of the weld depth detection.

[0033] Meanwhile, the field lens 105 is set at the output port of the processing head 1 to focus the measuring light 601 beam and the welding laser 301 beam after being deflected by the galvanometer assembly and then emit them onto the workpiece 8.

[0034] Preferably, a field lens protection lens 106 is also provided for the corresponding field lens 105. The field lens protection lens 106 is also provided at the output end of the processing head 1 to protect the field lens 105 and prevent dust, splashes and other objects from damaging the field lens 105.

[0035] Furthermore, in the preferred embodiment, the processing head 1 is disposed on the moving device 2 so that the moving device 2 drives the processing head 1 to move relative to the workpiece 8.

[0036] In actual setup, the mobile device 2 can be a multi-axis robot or a three-axis motion platform, as long as it can meet the movement requirements of the processing head 1. For example... Figure 1 As shown, in the preferred embodiment, the mobile device 2 is a multi-axis robot.

[0037] Furthermore, in the preferred embodiment, the main controller 7 is simultaneously connected to the laser processing device, the OCT detection device, and the moving device, so as to control and adjust the output parameters of the laser processing device, receive real-time melt depth data from the OCT detection device, and control the motion parameters of the moving device, thereby coordinating the collaborative work of each device.

[0038] Specifically, the main controller 7 includes a logic control system, which specifically includes a penetration depth analysis module, a defect location module, and a parameter optimization module. The penetration depth analysis module can perform real-time analysis and comparison between the penetration depth data fed back by the OCT detection device and a preset threshold to determine the area with insufficient penetration depth and the defect type. The defect location module is used to mark the coordinates of the area with insufficient penetration depth. The parameter optimization module includes a mapping relationship library between defect types and repair welding parameters, so as to automatically call repair welding parameters according to defect characteristics.

[0039] Accordingly, the main controller 7 can control the moving device 2 to move the processing head 1 to the corresponding position according to the coordinates, and control the laser processing device and the moving device 2 to adjust to the corresponding parameters according to the welding parameters, so as to perform welding on the area with insufficient penetration.

[0040] Preferably, the defect characteristics generally include gap defects caused by excessive gaps, as well as defects caused by pollution, dust, etc.; among which, the welding parameters for repairing gap defects include at least one of the following: increasing laser power by 0~30%, reducing welding speed by 0~50%, adjusting defocusing amount, increasing weld size by 0~2mm, etc. The larger the gap, the greater the adjustment range of the parameters.

[0041] Preferably, for adjusting the laser power during gap defect repair welding, the gap size and the repair welding laser power have the following relationship: Laser power for repair welding = normal laser power + k × gap size.

[0042] Where K is a coefficient, typically taken as 10~300W / 0.1mm.

[0043] Preferably, for defects caused by pollution, dust, etc., the beam output direction can be changed by adjusting the galvanometer assembly in real time or the welding program can be called after the welding path is completed.

[0044] Furthermore, the present invention also relates to an intelligent laser welding method, which utilizes the above-mentioned welding system for welding, such as... Figure 3 As shown, the specific steps include: (1) The laser processing device emits a welding laser 301 through the processing head 1 to perform laser welding on the weld of the workpiece 8; at the same time, the OCT detection device emits a measuring light 601 through the processing head 1 to obtain the weld penetration data in real time and transmits the penetration data to the main controller 7. (2) The penetration depth analysis module analyzes the penetration depth data; if insufficient penetration depth is detected, the penetration depth analysis module confirms the defect type and generates a repair welding instruction, and the defect location module marks the coordinates of the area with insufficient penetration depth; (3) After the welding path is completed, the main controller 7 controls the moving device 2 to move the processing head 1 above the defective weld according to the coordinates of the insufficient penetration area marked by the defect positioning module, and the repair weld covers the area within 1 mm around the defective weld. (4) The parameter optimization module automatically calls the repair welding parameters according to the defect characteristics. The main controller 7 controls the laser processing device and the moving device to perform repair welding operation according to the repair welding parameters. The OCT detection device detects the weld penetration depth of the repair weld in real time. (5) If the weld penetration depth of the repair weld is qualified, the welding of workpiece 8 is completed; if the weld penetration depth of the repair weld is not qualified, repeat steps (2) to (4) until the weld penetration depth of the repair weld is qualified, and the laser welding of workpiece 8 is completed.

[0045] Example 1: On the prismatic battery production line, the aforementioned intelligent laser welding system is used to weld the 1.5mm thick busbar and electrode post. The focused welding laser 301 performs welding along a 9.5mm diameter arc, with a normal power of 5700W and a welding speed of 130mm / s. An OCT detection device simultaneously monitors the bottom of the small hole in real time, tracking the weld penetration (if a gap greater than 0.3mm results in insufficient penetration on the lower plate and excessive surface depression, the penetration and depression indicators do not meet industry standards). The logic control system analyzes in real time, identifying gaps in areas with insufficient penetration within the 0.5~0.6mm range. It then quickly initiates a repair welding procedure with a repair welding power of 6000W and a welding speed of 120mm / s. After the welding path is completed, repair welding is performed at the welding station (in-situ instantaneous repair), improving product yield and efficiency.

[0046] Example 2: On the prismatic battery production line, the aforementioned intelligent laser welding system is used to weld the 2.5mm thick busbar and electrode post. During the main trajectory 11mm diameter circular arc welding of the focused welding laser, the power is 4500W, the speed is 60mm / s, and the defocusing amount is +2mm. The measuring light emitted by the OCT detection device synchronously detects the bottom of the small hole in real time, monitoring the weld depth. The logic control system analyzes in real time and identifies gaps in areas with insufficient weld depth within the range of 0.8~0.9mm. A rapid repair welding procedure is then initiated, with a repair welding power of 5300W, a repair welding speed of 60mm / s, and a defocusing amount of -2mm. Repair welding is performed at the welding station after the welding path is completed (in-situ instantaneous repair), improving product yield and efficiency.

[0047] The intelligent laser welding system and welding method of this invention have a simple structure and reasonable setup, integrating laser welding, inspection, and repair welding into one unit. During the laser welding process, the OCT inspection device acquires all weld penetration data in real time, and the logic control system analyzes the causes of insufficient penetration in real time. Based on the penetration analysis structure, the repair welding program is called for the areas with insufficient penetration, and the processing head is driven by a moving device to achieve in-situ repair welding. This solves the problem in traditional welding where insufficient penetration due to gaps or contamination requires secondary positioning and rework at a repair welding station. It simplifies the production process, improves processing efficiency and product yield, and reduces production costs, showing good application prospects and promotional value.

[0048] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An intelligent laser welding system, characterized in that, Includes laser processing equipment, OCT inspection equipment, processing head, moving device, and main controller; The output ends of both the laser processing device and the OCT detection device are located on the processing head, so that the welding laser emitted by the laser processing device and the measuring light emitted by the OCT detection device are coaxially emitted onto the workpiece through the processing head; and the measuring light returns to the OCT detection device along the original path after contacting the workpiece, so as to detect the weld penetration depth. The processing head is mounted on the moving device so that the moving device can drive the processing head to move relative to the workpiece; The main controller is connected to the laser processing device, the OCT detection device, and the mobile device; the main controller includes a logic control system, which includes a penetration depth analysis module, a defect location module, and a parameter optimization module. The penetration depth analysis module performs real-time analysis and comparison between the penetration depth data fed back by the OCT detection device and the preset threshold to determine the area with insufficient penetration depth and the type of defect, and generates a repair welding instruction. The defect location module is used to mark the coordinates of areas with insufficient penetration; the parameter optimization module includes a mapping relationship library between defect types and repair welding parameters, so as to automatically call the repair welding program according to the defect characteristics. After the welding path is completed, the main controller controls the moving device to move the processing head above the defective weld and perform a repair welding operation based on the coordinates of the insufficient penetration area marked by the defect location module. The defect type includes gap defects, and the welding parameters for repairing gap defects include increasing the laser power; The gap defect and the laser power for repair welding are related as follows: Repair welding laser power = normal laser power + k × gap size; Where K is a coefficient.

2. The intelligent laser welding system according to claim 1, characterized in that, The welding parameters for repairing the gap defect also include at least one of the following: reducing the welding speed by 0-50%, adjusting the defocusing amount, and increasing the weld size by 0-2 mm.

3. The intelligent laser welding system according to claim 1, characterized in that, The processing head includes a first beam splitter, a second beam splitter, a galvanometer assembly, and a field lens; The first beam splitter is configured to correspond to the laser processing device to reflect the welding laser to the galvanometer assembly; the second beam splitter is configured to correspond to the OCT detection device to reflect the measurement light to be coaxial with the welding laser and incident on the galvanometer assembly. The galvanometer assembly is used to adjust the output direction of the welding laser and the measuring light; The field lens is used to focus the welding laser and the measuring light and then emit them onto the workpiece.

4. The intelligent laser welding system according to claim 3, characterized in that, The galvanometer assembly includes an X-mirror and a Y-mirror arranged sequentially along the beam output direction. The X-mirror is used to deflect the beam in the X direction, and the Y-mirror is used to deflect the beam in the Y direction.

5. The intelligent laser welding system according to claim 3, characterized in that, The processing head also includes a field lens protection lens, which is disposed at the output end of the processing head to protect the field lens.

6. The intelligent laser welding system according to claim 1, characterized in that, The distance between the measuring light spot and the welding laser spot is less than 0.5 mm.

7. The intelligent laser welding system according to claim 1, characterized in that, The mobile device is a multi-axis robot or a three-axis motion platform.

8. The intelligent laser welding system according to any one of claims 1 to 7, characterized in that, The laser processing device includes a laser, a transmission optical fiber, and a chiller; one end of the transmission optical fiber is connected to the laser, and the other end is connected to the processing head to input the welding laser emitted by the laser to the processing head; The chiller is used to cool the laser.

9. A smart laser welding method, using the smart laser welding system according to any one of claims 1 to 8 for welding, characterized in that, Includes the following steps: (1) The laser processing device emits a welding laser through the processing head to perform laser welding on the workpiece weld; at the same time, the OCT detection device emits a measuring light through the processing head to obtain the weld penetration data in real time and transmits the penetration data to the main controller. (2) The penetration depth analysis module analyzes the penetration depth data. If an area with insufficient penetration depth is identified, the penetration depth analysis module confirms the defect type and generates a repair welding instruction. The defect location module marks the coordinates of the area with insufficient penetration depth. (3) After the welding path is completed, the main controller controls the moving device to move the processing head above the defective weld according to the coordinates of the insufficient penetration area marked by the defect positioning module, and the repair weld covers the area within 1 mm around the defective weld. (4) The parameter optimization module automatically calls the repair welding parameters according to the defect characteristics. The main controller controls the laser processing device and the moving device to perform repair welding operation according to the repair welding parameters. The OCT detection device detects the weld penetration depth of the repair weld in real time. (5) If the weld penetration depth of the repair weld is qualified, the welding of the workpiece is completed; if the weld penetration depth of the repair weld is not qualified, repeat steps (2) to (4) until the weld penetration depth of the repair weld is qualified, and the laser welding of the workpiece is completed.

Images