Bus bar laser welding quality detection method and device and computer storage medium
By monitoring the surface temperature of the welding part in real time and analyzing the temperature curve, the problem of low accuracy of traditional detection methods is solved, and higher accuracy and stability of welding quality detection are achieved.
Patent Information
- Application Number
- CN202311192340.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-15
- Publication Date
- 2025-03-18
AI Technical Summary
The traditional bus bar welding quality inspection method relies on appearance judgment, has low accuracy, and is prone to missed inspection and missed inspection.
By monitoring the surface temperature of the welding part in real time during the welding process, fitting the temperature curve of the surface temperature value of each welding line with time, and analyzing the temperature curves of all welding lines on the bus bar to determine whether the welding quality is qualified.
It improves detection accuracy, reduces the possibility of missed inspection and missed inspection, can more accurately reflect abnormalities during welding, and ensures the stability of welding quality.
Smart Images
Figure CN119643637A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of photovoltaic module production, and specifically to a busbar laser welding quality detection method, device and computer storage medium. Background Art
[0002] like Figure 1 As shown, when a laser welding device is used to weld a junction box 1 to a bus bar 2 on a photovoltaic module, the laser scans each bus bar 2 in batches, and each scan forms a welding line 3. In order to ensure the stability of welding quality, it is required to weld multiple welding lines 3 on each bus bar 2, for example Figure 1 Four of them.
[0003] After the busbar welding on the photovoltaic module is completed, the welding quality of the busbar needs to be tested. The traditional testing method is to use a camera to shoot the welded busbar, and judge whether the busbar and the junction box bonding strength meets the requirements based on the appearance quality of the welded busbar. However, the appearance inspection method has low detection accuracy and is prone to missed detection and false detection. Summary of the invention
[0004] In view of the above technical problems existing in the traditional busbar welding quality detection method, the present application provides a busbar laser welding quality detection method, and its detailed technical solution is as follows:
[0005] A busbar laser welding quality detection method is used to detect the welding quality of a busbar and a junction box after laser welding. The laser scans and welds a busbar to form N welding lines, where N is greater than 1. The busbar laser welding quality detection method includes:
[0006] During the welding process of each welding wire, the surface temperature value of the welding part is collected at predetermined time intervals;
[0007] Based on the collected surface temperature values, a temperature curve of the surface temperature value of each welding wire changing with time is fitted;
[0008] For each bus bar, the temperature curves of the N welding wires on the bus bar are analyzed to determine whether the welding quality of the bus bar is qualified.
[0009] This application monitors the surface temperature of the welding part in real time during the welding process, fits the change of the surface temperature of each welding wire over time during the welding process into a temperature curve, and judges whether the busbar welding quality is qualified by analyzing the temperature curves of all welding wires on the busbar. Compared with judging by appearance, this application can reflect welding anomalies in the welding process by monitoring the surface temperature of the welding part, thereby achieving the purpose of detecting welding quality, greatly improving the detection accuracy and reducing the possibility of missed detection and false detection.
[0010] In some embodiments, determining whether the welding quality of the busbar is qualified by analyzing the temperature curves of N welding wires on the busbar includes:
[0011] Calculate the overall temperature average X of the N welding wires on the bus bar based on the surface temperature values included in the temperature curves of the N welding wires on the bus bar;
[0012] If B≤X≤A, the welding quality of the busbar is determined to be qualified, wherein B is a preset lower limit value of the overall temperature, and A is a preset upper limit value of the overall temperature;
[0013] If X<B, the welding quality of the busbar is judged to be unqualified;
[0014] If X>A, the temperature curve of each welding wire on the busbar is analyzed separately to determine whether the welding quality of the busbar is qualified.
[0015] The present application provides an easy-to-implement method for determining whether the welding quality of a busbar is qualified. It determines whether the welding quality of the busbar is qualified by the overall temperature average of N welding wires on the busbar. The overall temperature average is used to make an initial judgment on whether the welding quality is qualified, and busbars with qualified and unqualified welding quality can be quickly identified, and busbars that need further judgment can be identified at the same time; if the overall temperature average is within a predetermined temperature range, it means that the welding quality of the busbar is qualified; if the overall temperature average is low, it means that the welding temperature is insufficient and the welding quality of the busbar must be unqualified; if the overall temperature average is high, it may be due to overburning that the welding quality is unqualified, or it may be because there are several abnormally high surface temperature values that raise the overall temperature average but the welding quality is actually qualified. By individually analyzing each welding wire on the busbar in this case and then determining the welding quality, misjudgment can be avoided.
[0016] In some embodiments, determining whether the welding quality of the busbar is qualified by individually analyzing the temperature curve of each welding wire on the busbar includes:
[0017] Analyze the temperature curve of each welding wire on the busbar separately to determine whether each welding wire is a qualified welding wire or a failed welding wire;
[0018] Whether the welding quality of the busbar is qualified is determined based on the information of the unqualified welding wire.
[0019] The invention provides an easy-to-implement method for determining whether the welding quality of the busbar is qualified according to the information of the unqualified welding line on the busbar.
[0020] In some embodiments, the temperature curve of each welding wire on the bus bar is analyzed separately to determine whether each welding wire is a qualified welding wire or an unqualified welding wire, including:
[0021] Based on the surface temperature value included in the temperature curve of the i-th welding wire on the bus bar, the average welding wire temperature X of the i-th welding wire on the bus bar is calculated. i , 1≤i≤N;
[0022] If D i ≤X i ≤C i , determine the i-th welding wire as a qualified welding wire, where D i is the preset lower limit of the welding wire temperature corresponding to the i-th welding wire in each busbar, C i is the preset upper limit value of the welding wire temperature suitable for the i-th welding wire in each busbar;
[0023] If X i <D i , the i-th welding wire on the busbar is determined to be an unqualified welding wire;
[0024] If X i >C i , an abnormal high temperature analysis is performed on the ith welding wire based on the temperature curve of the ith welding wire on the bus bar to determine whether the ith welding wire is a qualified welding wire or an unqualified welding wire.
[0025] By judging whether the mean temperature of each welding wire is within the preset temperature range corresponding to the welding wire, qualified welding wires and unqualified welding wires can be quickly identified, and welding wires that need further judgment can be identified; if the mean temperature of the welding wire is within the corresponding preset temperature range, it means that the welding of the welding wire is qualified; if the mean temperature of the welding wire is low, it means that the welding temperature is insufficient, and the welding quality of the welding wire must be unqualified; if the mean temperature of the welding wire is high, it may be due to overburning, resulting in unqualified welding, or it may be due to the presence of several abnormally high surface temperature values that affect the mean temperature of the welding wire. By performing abnormal high temperature analysis on the welding wire in this case again, misjudgment can be avoided. Since the welding positions and welding sequences of each welding wire are different, the lower limit and upper limit of the welding wire temperature of each welding wire are set in a targeted manner to further improve the detection accuracy.
[0026] In some embodiments, the temperature curve of each welding wire on the bus bar is analyzed separately to determine whether each welding wire is a qualified welding wire or an unqualified welding wire, including:
[0027] Based on the surface temperature value included in the temperature curve of the i-th welding wire on the bus bar, the average welding wire temperature X of the i-th welding wire on the bus bar is calculated. i , 1≤i≤N;
[0028] If D≤X i≤C, the i-th welding wire is determined to be a qualified welding wire, wherein D is the preset lower limit of welding wire temperature, and C is the preset upper limit of welding wire temperature;
[0029] If X i <D, the i-th welding wire on the busbar is determined to be an unqualified welding wire;
[0030] If X i >C, an abnormal high temperature analysis is performed on the i-th welding wire based on the temperature curve of the i-th welding wire on the bus bar to determine whether the i-th welding wire is a qualified welding wire or an unqualified welding wire.
[0031] By judging whether the mean temperature of each welding wire is within the preset temperature range, qualified welding wires and unqualified welding wires can be quickly identified, and welding wires that need further judgment can be identified; if the mean temperature of the welding wire is within the preset temperature range, it means that the welding of this welding wire is qualified; if the mean temperature of the welding wire is low, it means that the welding temperature is insufficient and the welding quality of this welding wire must be unqualified; if the mean temperature of the welding wire is high, it may be due to overburning, resulting in unqualified welding, or it may be due to the presence of several abnormally high surface temperature values that affect the mean temperature of the welding wire. By performing abnormal high temperature analysis on the welding wire in this case again, misjudgment can be avoided. The lower limit value and upper limit value of the welding wire temperature of all welding wires are uniformly set to simplify the detection process.
[0032] In some embodiments, performing abnormal high temperature analysis on the i-th welding wire based on the temperature curve of the i-th welding wire on the bus bar to determine whether the i-th welding wire is a qualified welding wire or an unqualified welding wire includes:
[0033] Count the number of surface temperature values higher than the abnormally high temperature threshold E among the surface temperature values included in the temperature curve of the i-th welding wire on the busbar, wherein the abnormally high temperature threshold E is greater than the upper limit value C of the welding wire temperature. i Or the upper limit of the welding wire temperature C;
[0034] If the number of surface temperature values higher than the abnormally high temperature threshold E is greater than the abnormally high temperature point number threshold Z, the i-th welding wire is determined to be an unqualified welding wire;
[0035] If the number of surface temperature values higher than the abnormally high temperature threshold value E is not greater than the abnormally high temperature point number threshold value Z, the i-th welding wire is determined to be a qualified welding wire.
[0036] By setting an abnormally high temperature threshold E and counting the number of surface temperature values contained in the temperature curve of the i-th welding wire on the busbar that are higher than the abnormally high temperature threshold E, the number of temperature points belonging to abnormally high temperatures in the welding wires can be identified. By comparing and analyzing the number of points with the abnormally high temperature point number threshold Z, it is possible to identify which welding wires are welded at the allowable abnormally high temperature, i.e., qualified welding wires, and which welding wires are not welded at the allowable abnormally high temperature, i.e., unqualified welding wires.
[0037] In some embodiments, the information of the unqualified welding wires includes the number and position of the unqualified welding wires, and determining whether the welding quality of the busbar is qualified according to the information of the unqualified welding wires includes:
[0038] Determine whether the welding quality of the busbar is qualified based on the number of unqualified welding lines; or
[0039] Whether the welding quality of the busbar is qualified is determined based on the number and position of the unqualified welding lines.
[0040] By counting the number of unqualified welding wires, or combining the number and location of unqualified welding wires, it is possible to effectively determine whether the welding quality of the busbar is qualified.
[0041] In some embodiments, after determining whether each welding line is a qualified welding line or an unqualified welding line, the busbar laser welding quality detection method further includes:
[0042] At least perform an attribution analysis on the failed wirebonds on the busbar to determine the cause of the failed wirebond or busbar.
[0043] By conducting attribution analysis on unqualified welding wires, a basis is provided for subsequent junction box re-soldering, rework and product quality traceability.
[0044] In some embodiments, at least performing attribution analysis on the unqualified welding wires on the bus bar to determine the cause of the unqualified welding wires or bus bars includes:
[0045] Calculate the starting welding temperature value and / or the slope of the temperature curve of each unqualified welding wire in the busbar, or calculate the starting welding temperature value and / or the slope of the temperature curve of each unqualified welding wire and qualified welding wire in the busbar, wherein the starting welding temperature value is the average of the first M surface temperature values in the temperature curve of the welding wire;
[0046] If the initial welding temperature value is greater than the initial welding temperature threshold F, it is determined that the reason for the failure of the welding wire or bus bar is that the bus bar surface is dirty;
[0047] If the slope of the temperature curve of the welding wire is greater than the slope threshold value K, it is determined that the reason for the failure of the welding wire or the bus bar is a gap between the bus bar and the junction box.
[0048] An implementation method for performing attribution analysis on unqualified bond wires is provided, which can determine two main causes of unqualified bond wires.
[0049] In some embodiments, collecting the surface temperature value of the welding part at every predetermined time interval includes: collecting the intensity of the thermal radiation light radiated from the welding part by an infrared temperature measuring device at every predetermined time interval.
[0050] A non-contact temperature measurement method is provided, which implements the rapid acquisition of the surface temperature value of the welding part.
[0051] The present application also provides a busbar laser welding quality detection device, which includes a memory and a processor, wherein the memory stores at least one program instruction, and the processor implements any of the above-mentioned busbar laser welding quality detection methods by loading and executing at least one program instruction.
[0052] The present application also provides a computer storage medium, in which at least one program instruction is stored, and the at least one program instruction is loaded and executed by a processor to implement any of the above-mentioned busbar laser welding quality detection methods. BRIEF DESCRIPTION OF THE DRAWINGS
[0053] Figure 1 The figure is a schematic diagram of the welding between the busbar and the junction box;
[0054] Figure 2 is a flowchart of the execution of the busbar laser welding quality detection method in the embodiment of the present application;
[0055] Figure 3 This is a schematic diagram of a method for collecting the surface temperature value of a welding part by an infrared temperature measuring device in one embodiment of the present application;
[0056] Figure 4 This is a schematic diagram of a method for collecting the surface temperature value of a welding part by an infrared temperature measuring device in another embodiment of the present application;
[0057] Figure 5 The temperature curves of all bus bars on the photovoltaic module fitted by the embodiment of the present application;
[0058] Figure 6 The temperature curves of all bus bars on the photovoltaic module fitted in Example 1 of the present application;
[0059] Figure 7 The temperature curves of all bus bars on the photovoltaic module fitted in Example 2 of the present application;
[0060] Figure 8 The temperature curves of all bus bars on the photovoltaic module fitted in Example 3 of the present application;
[0061] Fig. 9 The temperature curves of all bus bars on the photovoltaic module fitted in Example 4 of the present application;
[0062] Fig.10 The temperature curves of all bus bars on the photovoltaic module fitted in Example 5 of the present application;
[0063] Fig.11 The temperature curves of all bus bars on the photovoltaic module fitted in Example 6 of the present application;
[0064] Figures 1 to 11 Included:
[0065] Junction box 1, bus bar 2, welding wire 3, infrared temperature measuring device 4, laser 5, galvanometer 6, field lens 7, first beam splitter 8, second beam splitter 9. DETAILED DESCRIPTION
[0066] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.
[0067] The technical solution of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.
[0068] When a laser welding device is used to weld the junction box and the busbars on the photovoltaic module, the laser scans each busbar in batches, and each scan forms a welding line.
[0069] In order to ensure the welding quality of the busbar, the welding temperature must be controlled within a predetermined temperature range during the laser welding of the busbar. If the welding temperature is too low, the welding part cannot be fully melted, and the busbar cannot be welded to the junction box; if the welding temperature is too high, the busbar may be overburned. This application proposes to monitor the surface temperature of the welding part in real time during the welding process, and analyze the welding quality of all welding wires on the busbar based on this, and finally determine whether the busbar welding quality is qualified.
[0070] The present application proposes a busbar laser welding quality detection method, which is used to detect the welding quality of a busbar and a junction box after laser welding, wherein the laser scans and welds a busbar to form N welding lines, where N is a natural number greater than 1.
[0071] like Figure 2 As shown, the busbar laser welding quality detection method in the embodiment of the present application includes the following steps:
[0072] Step 101 : During the welding process of each welding wire, the surface temperature value of the welding part is collected at every predetermined time interval.
[0073] Step 102: Based on the collected surface temperature values, a temperature curve of the surface temperature value of each welding wire changing with time is fitted.
[0074] Step 103 : For each bus bar, determine whether the welding quality of the bus bar is qualified by analyzing the temperature curves of the N welding wires on the bus bar.
[0075] In step 101, during the welding process of each welding wire, the surface temperature value of the welding part is collected at predetermined time intervals. An optional collection method is to collect the thermal radiation light radiated from the welding part at predetermined time intervals (such as 1ms) by an infrared temperature measuring device to obtain the surface temperature value of the welding part.
[0076] like Figure 3 As shown, in an optional implementation, the infrared temperature measuring device 4 and the laser 5 are arranged in a paraxial manner, and the infrared temperature measuring device 4 is arranged on the side of the laser 5, tilted and facing the bus bar 2. During the process of scanning and forming the welding line 3 by the laser 5, the thermal radiation light radiated from the welding part directly enters the infrared temperature measuring device 4.
[0077] like Figure 4 As shown, in another optional implementation, the infrared temperature measuring device 4 and the laser 5 are coaxially arranged, the galvanometer 6, the first beam splitter 8 and the second beam splitter 9 are coaxially arranged, and the field lens 7 is arranged on the reflected light path of the galvanometer 6; the laser 5 is arranged on the reflected light path of the first beam splitter 8, and the infrared temperature measuring device 4 is arranged on the reflected light path of the second beam splitter 9.
[0078] The process of laser welding and temperature collection is as follows:
[0079] The welding laser emitted by the laser 5 passes through the first beam splitter 8 and enters the galvanometer 6. The galvanometer 6 polarizes the welding laser so that the welding laser focused by the field lens 7 scans on the bus bar to form a welding line 3.
[0080] In this process, the thermal radiation light radiated from the welding part enters the second beam splitter 9 after passing through the field lens 7, the galvanometer 6, and the first beam splitter 8 in sequence, and is reflected into the infrared temperature measuring device 4 through the reflection light path of the second beam splitter 9.
[0081] In step 102 , based on the collected surface temperature values, a temperature curve of the surface temperature value of each welding wire changing with time is fitted.
[0082] After the surface temperature value is collected in the above manner, a temperature curve of the surface temperature value of each welding wire changing with time can be fitted based on the collected multiple surface temperature values. The curve fitting method can adopt an existing algorithm, such as a least squares method, an interpolation method, or other curve fitting algorithm to fit the temperature curve of the surface temperature value of each welding wire changing with time.
[0083] For example, in one embodiment, three junction boxes need to be welded on a photovoltaic module, wherein each junction box needs to be welded with two bus bars, i.e., a total of 6 bus bars need to be welded. During the welding process, the laser scans on each bus bar to form 4 welding lines (i.e., N is 4), and finally a total of 24 welding lines are formed on a photovoltaic module.
[0084] Figure 5 The curve shown is a temperature curve of the surface temperature values of the 24 welding wires in the above photovoltaic module changing with time, wherein: Figure 5 The curve shown in the dashed box a is a temperature curve corresponding to a welding wire. The four adjacent temperature curves (such as Figure 5 The dashed box b in the figure corresponds to the four welding wires on the same busbar, and the interval between two adjacent temperature curves (such as Figure 5 The solid line box c in FIG. 1 corresponds to the welding time interval between the two welding wires.
[0085] After fitting the temperature curve, for each bus bar, the temperature curves of the N welding wires on the bus bar are analyzed to determine whether the welding quality of the bus bar is qualified.
[0086] It can be seen that the busbar laser welding quality detection method provided by the embodiment of the present application monitors the surface temperature of the welding part in real time during the welding process, fits the change of the surface temperature of each welding wire during the welding process with time into a temperature curve, and judges whether the busbar welding quality is qualified by analyzing the temperature curves of all welding wires on the busbar. Compared with judging the welding quality by appearance, the embodiment of the present application can reflect the welding abnormality in the welding process by monitoring the surface temperature of the welding part, thereby achieving the purpose of detecting the welding quality, thereby greatly improving the detection accuracy and reducing the possibility of missed detection and false detection.
[0087] Optionally, in a possible implementation, the above step 103 of analyzing the temperature curves of the N welding wires on the busbar to determine whether the welding quality of the busbar is qualified includes the following steps:
[0088] Step S11 : calculating an overall temperature average X of the N welding wires on the bus bar based on the surface temperature values included in the temperature curves of the N welding wires on the bus bar.
[0089] Step S12: compare the overall temperature mean value X with the overall temperature lower limit value B and the overall temperature upper limit value A, and determine whether the welding quality of the busbar is qualified according to the comparison result, specifically:
[0090] Case 1: When B≤X≤A:
[0091] It shows that during the busbar welding process, the surface temperature values of most welding parts are within the predetermined temperature range B to A. In this case, it can be ensured that the busbar is firmly welded to the junction box. Therefore, it can be determined that the welding quality of the busbar is qualified.
[0092] Case 2: When X<B:
[0093] This indicates that during the busbar welding process, there are a large number of welding locations where the surface temperature is lower than the overall temperature lower limit B, that is, the welding temperature is insufficient and the busbar cannot be firmly welded to the junction box. Therefore, it can be determined that the welding quality of the busbar is unqualified.
[0094] Case 3: When X>A:
[0095] It shows that during the busbar welding process, there may be a large number of welding parts with surface temperature values higher than the overall temperature upper limit A, and there may also be a small number of welding parts with surface temperature values much higher than the overall temperature upper limit A. The number of these surface temperature values higher than the overall temperature upper limit A, their position distribution on each welding line, and the height of the surface temperature values will affect the judgment of the busbar welding quality.
[0096] Therefore, in the third situation, in order to accurately determine whether the welding quality of the busbar is qualified, the present application further adopts a separate analysis of the temperature curve of each welding wire on the busbar to determine whether the welding quality of the busbar is qualified.
[0097] The above-mentioned overall temperature lower limit value B and overall temperature upper limit value A are related to factors such as welding process parameters and are empirical values. They need to be set according to specific circumstances in actual production.
[0098] Optionally, when the aforementioned situation three occurs, the temperature curve of each welding wire on the busbar is analyzed separately to determine whether the welding quality of the busbar is qualified, including the following steps:
[0099] Step S121 : Analyze the temperature curve of each welding wire on the busbar separately to determine whether each welding wire is a qualified welding wire or an unqualified welding wire.
[0100] Step S122: Determine whether the welding quality of the busbar is qualified according to the information of the unqualified welding wire.
[0101] Optionally, the execution process of step S121 is as follows:
[0102] Based on the surface temperature value included in the temperature curve of the i-th welding wire on the bus bar, the average welding wire temperature X of the i-th welding wire on the bus bar is calculated. i , 1≤i≤N.
[0103] If D i ≤X i ≤C i , determine the i-th welding wire as a qualified welding wire, where D i is the preset lower limit of the welding wire temperature corresponding to the i-th welding wire in each busbar, C i is a preset upper limit value of the welding wire temperature corresponding to the i-th welding wire in each busbar.
[0104] If X i <D i , the i-th welding wire on the busbar is determined to be an unqualified welding wire.
[0105] If X i >C i , an abnormal high temperature analysis is performed on the ith welding wire based on the temperature curve of the ith welding wire on the bus bar to determine whether the ith welding wire is a qualified welding wire or an unqualified welding wire.
[0106] Among them, the lower limit of the welding wire temperature suitable for the i-th welding wire is D i , upper limit of welding wire temperature C i It is related to factors such as the welding sequence of welding wires and welding process parameters. It is an empirical value and needs to be set according to specific circumstances in actual production.
[0107] Since the welding positions and welding sequences of the welding wires are different, in the above embodiment, the lower limit value and the upper limit value of the welding wire temperature of each welding wire are specifically set to improve the detection accuracy.
[0108] Of course, if the detection accuracy requirement is not high, the lower limit value and the upper limit value of the welding wire temperature of each welding wire can also be set uniformly. In this case, the execution process of step S121 is as follows:
[0109] Based on the surface temperature value included in the temperature curve of the i-th welding wire on the bus bar, the average welding wire temperature X of the i-th welding wire on the bus bar is calculated. i , 1≤i≤N;
[0110] If D≤X i ≤C, the i-th welding wire is determined to be a qualified welding wire, wherein D is the preset lower limit of welding wire temperature, and C is the preset upper limit of welding wire temperature;
[0111] If X i <D, the i-th welding wire on the busbar is determined to be an unqualified welding wire;
[0112] If X i >C, an abnormal high temperature analysis is performed on the i-th welding wire based on the temperature curve of the i-th welding wire on the bus bar to determine whether the i-th welding wire is a qualified welding wire or an unqualified welding wire.
[0113] After conducting a large number of welding tests, we found that the i >C i or X i There are at least two possible situations for C:
[0114] Case 1: The temperature curve of the i-th welding wire contains a large number of abnormally high surface temperature values, which means that a relatively long portion of the welding wire segment of the i-th welding wire is welded at an abnormally high temperature. In this case, the i-th welding wire should be determined as an unqualified welding wire.
[0115] Scenario 2: The temperature curve of the i-th welding wire contains a small amount of abnormally high surface temperature values, which means that only a short portion of the welding wire segment of the i-th welding wire is welded at an abnormally high temperature. If the length of the welding wire segment welded at an abnormally high temperature accounts for a small proportion of the length of the entire welding wire and does not affect the welding strength of the entire welding wire, then the welding wire can be determined as a qualified welding wire.
[0116] In order to identify the qualified welding wire in the above situation 2, optionally, an abnormal high temperature analysis is performed on the i-th welding wire based on the temperature curve of the i-th welding wire on the bus bar to determine whether the i-th welding wire is a qualified welding wire or an unqualified welding wire, including:
[0117] Count the number of surface temperature values higher than the abnormally high temperature threshold E among the surface temperature values included in the temperature curve of the i-th welding wire on the busbar, wherein the abnormally high temperature threshold E is greater than the upper limit value C of the welding wire temperature. i Or the upper limit of the welding wire temperature C.
[0118] If the number of surface temperature values higher than the abnormally high temperature threshold E is greater than the abnormally high temperature point number threshold Z, it means that the number of abnormally high temperature points is large, and the length of the i-th welding wire welded at abnormally high temperature is long, and the i-th welding wire is determined to be an unqualified welding wire.
[0119] If the number of surface temperature values higher than the abnormally high temperature threshold E is not greater than the abnormally high temperature point number threshold Z, it means that the number of abnormally high temperature points is small, and the length of the i-th welding wire welded at abnormally high temperature is short, and the i-th welding wire is determined to be a qualified welding wire.
[0120] In the aforementioned step S122, the busbar welding quality is determined to be qualified based on the information of the unqualified welding wires, wherein the information of the unqualified welding wires includes the number and position of the unqualified welding wires. The busbar welding quality is determined to be qualified based on the information of the unqualified welding wires, including:
[0121] Whether the welding quality of the busbar is qualified is judged only based on the number of unqualified welding lines. Whether the welding quality of the busbar is qualified can also be judged by comprehensively considering the number and position of the unqualified welding lines.
[0122] Optionally, the fewer the number of unqualified welding wires, the more the positions of the unqualified welding wires are located closer to the inside of the N welding wires, that is, when the unqualified welding wires are non-edge welding wires, the higher the welding quality of the busbar is.
[0123] Specific judgment criteria can be set according to actual production needs. For example, when the welding quality requirements are strict, the standard for qualified busbar welding quality is that the number of unqualified welding wires on the busbar is 0; when the welding quality requirements are loose, the number of unqualified welding wires on the busbar can be less than two as the criterion for judging the busbar to be qualified.
[0124] Still taking the example of forming four welding wires on the busbar, when the requirements for welding quality are relatively loose, the standard for judging whether the welding quality of the busbar is qualified can be set as: the number of unqualified welding wires must be less than two, and the position of the unqualified welding wires is close to the inner side of the four welding wires, that is, non-edge welding wires.
[0125] Optionally, after performing the above step S121 of determining whether each welding line is a qualified welding line or an unqualified welding line, the busbar laser welding quality detection method in the embodiment of the present application further includes:
[0126] Step S123: performing attribution analysis on at least the unqualified welding wires on the bus bar to determine the reasons causing the welding wires or the bus bar to be unqualified.
[0127] The purpose of determining the cause of unqualified welding wires includes providing a basis for subsequent junction box re-soldering, rework and product quality traceability.
[0128] Optionally, in the embodiment of the present application, at least performing attribution analysis on the unqualified welding wire on the bus bar to determine the cause of the unqualified welding wire or bus bar includes the following steps:
[0129] Step S1231, calculating the starting welding temperature value and / or the slope of the temperature curve of each unqualified welding wire in the busbar, or calculating the starting welding temperature value and / or the slope of the temperature curve of each unqualified welding wire and qualified welding wire in the busbar, wherein the starting welding temperature value is the average of the first M surface temperature values in the temperature curve of the welding wire.
[0130] For example, if the value of M is 10, the average of the first 10 surface temperature values in the temperature curve is taken as the starting welding temperature value.
[0131] If the initial welding temperature value is greater than the initial welding temperature threshold F, it is determined that the reason for the failure of the welding wire or the bus bar is that there is dirt on the surface of the bus bar.
[0132] The dirt on the busbar surface is mostly glue left over from the previous process. When there is glue on the busbar surface, during the welding process, the heat released by the glue is greater than the heat released by the busbar, which will cause the surface temperature of the welding part to rise sharply, and finally reflected in the temperature curve of the welding line that the starting welding temperature value is higher than the starting welding temperature threshold F.
[0133] If the slope of the temperature curve of the welding wire is greater than the slope threshold value K, it is determined that the reason for the failure of the welding wire or the bus bar is a gap between the bus bar and the junction box.
[0134] In order to ensure the quality of welding, before using laser welding to weld the busbar and the junction box, a clamping mechanism is required to press the busbar against the junction box to ensure that the busbar and the junction box fit tightly. However, in the actual production process, due to the different degrees of differences in the clamping effect of the clamping mechanism and the busbar itself may also have wrinkles and other factors, there will be a gap between the busbar and the junction box. The existence of the gap will affect the transfer of welding heat to the junction box, causing the surface temperature of the busbar to gradually accumulate and increase, which is ultimately reflected in the increase in the slope of the temperature curve of the weld line.
[0135] The above-mentioned starting welding temperature threshold F and slope threshold K are both empirical values, which are related to the welding process parameters. The specific values can be selected and set according to the specific situation.
[0136] In order to enable those skilled in the art to more clearly understand the technical solution of the busbar laser welding quality detection method of the present application, the detection process of the busbar laser welding quality detection method of the present application will be exemplarily described below through 6 embodiments.
[0137] Example 1
[0138] Welding requirements: Three junction boxes need to be welded to the photovoltaic module, and each junction box needs to be welded with two bus bars, that is, a total of 6 bus bars need to be welded. During the welding process, the laser scans each bus bar to form 4 welding lines. In the end, a total of 24 welding lines are formed on a photovoltaic module.
[0139] The welding process parameters are: laser welding power 800W, welding speed 40mm / s.
[0140] The preset judgment standard values are as follows:
[0141] The overall temperature lower limit value B is 470°C, and the overall temperature upper limit value A is 540°C.
[0142] The uniform lower limit value D of the welding wire temperature is 460°C, and the uniform upper limit value C of the welding wire temperature is 590°C.
[0143] The abnormally high temperature threshold E is 600°C, and the abnormally high temperature point number threshold Z is 30.
[0144] The initial soldering temperature threshold F is 480°C.
[0145] The slope threshold K is 2.
[0146] Execute steps 101 and 102, and the present embodiment obtains Figure 6 The temperature profiles of all 24 bond wires on 6 busbars are shown.
[0147] Next, step 103 is executed, that is, for each bus bar, the temperature curves of the four welding wires on the bus bar are analyzed to determine whether the welding quality of the bus bar is qualified.
[0148] The specific process is as follows:
[0149] Based on the surface temperature values included in the temperature curves of the four welding wires on each bus bar, the overall temperature average X of each bus bar is calculated. The calculation results are shown in Table 1.
[0150] Among them: the overall temperature average X of the first busbar is 505°C, the overall temperature average X of the second busbar is 495°C, the overall temperature average X of the third busbar is 476°C, the overall temperature average X of the fourth busbar is 488°C, the overall temperature average X of the fifth busbar is 471°C, and the overall temperature average X of the fifth busbar is 476°C.
[0151] Since the overall temperature average values X of the six busbars are all between the overall temperature lower limit value B and the overall temperature upper limit value A (ie, between 470° C. and 540° C.), it can be determined that the six busbars are all qualified busbars.
[0152] Table 1. Quality analysis results of the components of Example 1
[0153]
[0154] Example 2
[0155] The welding requirements, welding process parameters and pre-set judgment standard values of this embodiment are the same as those of embodiment 1.
[0156] Execute steps 101 and 102, and the present embodiment obtains Figure 7 The temperature profiles of all 24 bond wires on 6 busbars are shown.
[0157] Next, step 103 is executed, that is, for each bus bar, the temperature curves of the four welding wires on the bus bar are analyzed to determine whether the welding quality of the bus bar is qualified.
[0158] The specific process is as follows:
[0159] Based on the surface temperature values contained in the temperature curves of the four welding wires on each busbar, the overall temperature average X of each busbar is calculated, as shown in Table 2.
[0160] Among them: the overall temperature average X of the first busbar is 477°C, the overall temperature average X of the second busbar is 494°C, the overall temperature average X of the third busbar is 472°C, the overall temperature average X of the fourth busbar is 481°C, the overall temperature average X of the fifth busbar is 542°C, and the overall temperature average X of the sixth busbar is 492°C.
[0161] The overall temperature average values X of the 1st, 2nd, 3rd, 4th and 6th busbars are all between the overall temperature lower limit value B and the overall temperature upper limit value A (i.e., between 470°C and 540°C). Therefore, the welding quality of these busbars can be determined to be qualified.
[0162] The overall temperature average X of the 5th busbar is greater than the overall temperature upper limit A. Therefore, it is necessary to analyze the temperature curve of each welding line on the 5th busbar separately to further determine whether the welding quality of the 5th busbar is qualified. Specifically:
[0163] Calculate the average wire temperature X of each wire on the 5th busbar i , see Table 2, where the average wire temperature of the first wire is X 1 The average wire temperature of the second wire is 513℃. 2 The average wire temperature of the third wire is 520℃. 3 The average wire temperature of the fourth wire is 555°C. 4 It is 581℃.
[0164] Since the average values of the welding wire temperatures of the four welding wires on the fifth busbar are all between a unified welding wire temperature lower limit value D and a unified welding wire temperature upper limit value C (i.e., between 460°C and 590°C), the four welding wires are all qualified welding wires, and the fifth busbar is determined to be a qualified busbar.
[0165] That is to say, in this embodiment, all six bus bars are qualified bus bars.
[0166] Table 2. Quality analysis results of the components of Example 2
[0167]
[0168] Example 3
[0169] The welding requirements, welding process parameters and pre-set judgment standard values in this embodiment are the same as those in Embodiment 1.
[0170] Execute steps 101 and 102, and the present embodiment obtains Figure 8 The temperature profiles of all 24 bond wires on 6 busbars are shown.
[0171] Next, step 103 is executed, that is, for each bus bar, the temperature curves of the four welding wires on the bus bar are analyzed to determine whether the welding quality of the bus bar is qualified.
[0172] The specific process is as follows:
[0173] Based on the surface temperature values contained in the temperature curves of the four welding wires on each busbar, the overall temperature average X of each busbar is calculated, as shown in Table 3.
[0174] Among them: the temperature average value X of the first busbar is 612°C, the temperature average value X of the second busbar is 495°C, the temperature average value X of the third busbar is 468°C, the temperature average value X of the fourth busbar is 485°C, the temperature average value X of the fifth busbar is 472°C, and the temperature average value X of the sixth busbar is 473°C.
[0175] The overall temperature average values X of the second, fourth, fifth and sixth busbars are all between the overall temperature lower limit value B and the overall temperature upper limit value A (ie, between 470° C. and 540° C.), therefore, these busbars can be determined as qualified busbars.
[0176] The overall temperature average value X of the third bus bar is lower than the overall temperature lower limit value B, so the third bus bar can be determined as a failed bus bar.
[0177] The overall temperature average X of the first busbar is greater than the overall temperature upper limit A. Therefore, it is necessary to analyze the temperature curve of each welding line on the first busbar separately to further determine whether the welding quality of the first busbar is qualified. Specifically:
[0178] Calculate the average temperature X of each welding wire on the first busbar i , see Table 3, where the average temperature of the first welding wire is X 1 The average wire temperature of the second wire is 589℃. 2 The average wire temperature of the third wire is 613℃. 3 The average wire temperature of the fourth wire is 627℃. 4 It is 625℃.
[0179] The average temperature of the first welding wire is between the uniform lower limit of the welding wire temperature D and the uniform upper limit of the welding wire temperature C (i.e., between 460°C and 590°C), so the first welding wire can be determined as a qualified welding wire. The average temperatures of the second, third, and fourth welding wires are all greater than the uniform upper limit of the welding wire temperature C, so it is necessary to further perform abnormal high temperature analysis on these welding wires to determine whether these welding wires are qualified or unqualified.
[0180] By performing abnormal high temperature analysis on the second, third and fourth welding wires, the following results were obtained, see Table 3:
[0181] In the temperature curve of the second welding line, the number of surface temperature values higher than the abnormally high temperature threshold E is 71, which is greater than the abnormally high temperature point number threshold Z. Therefore, the second welding line can be determined as an unqualified weld line.
[0182] In the temperature curve of the third welding wire, the number of surface temperature values higher than the abnormally high temperature threshold E is 60, which is greater than the abnormally high temperature point number threshold Z. Therefore, the third welding wire can be determined as an unqualified welding wire.
[0183] In the temperature curve of the fourth welding wire, the number of surface temperature values higher than the abnormally high temperature threshold E is 66, which is greater than the abnormally high temperature point number threshold Z. Therefore, the fourth welding wire can be determined as an unqualified welding wire.
[0184] In this embodiment, when the number of unqualified welding wires is 0 as the criterion for determining a qualified bus bar, the first bus bar is ultimately determined to be a unqualified bus bar.
[0185] In addition, in this embodiment, the four welding wires on the first bus bar are also attributed and analyzed, as shown in Table 3, where:
[0186] The starting welding temperature values of the 2nd welding wire, the 3rd welding wire and the 4th welding wire (the average value of the starting 10 surface temperature values on the temperature curve) are 484°C, 546°C and 546°C respectively, all of which are greater than the starting welding temperature threshold F. Therefore, it can be determined that there is glue on the busbar surface.
[0187] The slope values of the first bus bar, the second welding wire, the third welding wire and the fourth welding wire are 5.61, 4.59, 2.22 and 2.57 respectively, which are all greater than the slope threshold K. It can be determined that there is a gap between the bus bar and the junction box.
[0188] Table 3. Quality analysis results of the components of Example 3
[0189]
[0190] Example 4
[0191] The welding requirements, welding process parameters and pre-set judgment standard values are the same as those in Example 1.
[0192] Execute steps 101 and 102, and the present embodiment obtains Fig. 9 The temperature profiles of all 24 wire bonds on the 6 bus bars are shown.
[0193] Next, step 103 is executed, that is, for each bus bar, the temperature curves of the four welding wires on the bus bar are analyzed to determine whether the welding quality of the bus bar is qualified.
[0194] The specific process is as follows:
[0195] Based on the surface temperature values contained in the temperature curves of the four welding wires on each busbar, the overall temperature average X of each busbar is calculated, as shown in Table 4.
[0196] Among them: the temperature average value X of the first busbar is 483°C, the temperature average value X of the second busbar is 476°C, the temperature average value X of the third busbar is 481°C, the temperature average value X of the fourth busbar is 577°C, the temperature average value X of the fifth busbar is 478°C, and the temperature average value X of the sixth busbar is 502°C.
[0197] The overall temperature average values X of the 1st, 2nd, 3rd, 5th and 6th busbars are all between the overall temperature lower limit value B and the overall temperature upper limit value A (i.e., between 470°C and 540°C). Therefore, the welding quality of these busbars can be determined to be qualified.
[0198] The overall temperature average X of the 4th busbar is greater than the overall temperature upper limit A. Therefore, it is necessary to analyze the temperature curve of each welding line on the 4th busbar separately to further determine whether the welding quality of the 4th busbar is qualified. Specifically:
[0199] Calculate the average temperature X of each welding wire on the fourth busbar i , see Table 4, where the average wire temperature of the first wire is X 1 The average wire temperature of the second wire is 536℃. 2 The average wire temperature of the third wire is 600℃, X 3 The average wire temperature of the fourth wire is 571°C. 4 It is 581℃.
[0200] The average values of the welding wire temperatures of the first welding wire, the third welding wire, and the fourth welding wire are between a uniform welding wire temperature lower limit value D and a uniform welding wire temperature upper limit value C (i.e., between 460° C. and 590° C.), and therefore, the first welding wire can be determined as a qualified welding wire.
[0201] The average temperature of the second welding wire is greater than the uniform upper temperature limit C of the welding wire. Therefore, it is necessary to perform further abnormal high temperature analysis on the second welding wire to determine whether the second welding wire is a qualified welding wire or an unqualified welding wire.
[0202] By performing abnormal high temperature analysis on the second welding wire, the following results were obtained, see Table 4:
[0203] In the temperature curve of the second welding wire, the number of surface temperature values higher than the abnormally high temperature threshold E is 58, which is greater than the abnormally high temperature point number threshold Z. Therefore, the second welding wire can be determined as an unqualified welding wire.
[0204] In this embodiment, when the number of unqualified welding wires is 0 as the criterion for determining a qualified bus bar, the fourth bus bar is ultimately determined to be an unqualified bus bar.
[0205] In addition, in this embodiment, the four welding wires on the fourth bus bar are also attributed to analysis, see Table 4, where:
[0206] The starting welding temperature values of the 1st welding wire, the 2nd welding wire, the 3rd welding wire and the 4th welding wire (the average value of the starting 10 surface temperature values on the temperature curve) are 454°C, 406°C, 477°C and 460°C respectively, which are all less than the starting welding temperature threshold F. Therefore, it can be determined that there is no glue on the busbar surface.
[0207] The slope values of the first welding line, the second welding line, the third welding line and the fourth welding line are 2.24, 5.24, 2.27 and 4.70 respectively, which are all greater than the slope threshold K. Therefore, it can be determined that there is a gap between the bus bar and the junction box.
[0208] Table 4. Quality analysis results of the components of Example 4
[0209]
[0210] Example 5
[0211] The welding requirements and welding process parameters are the same as those in Example 1.
[0212] The preset judgment standard values are as follows:
[0213] The overall temperature lower limit value B is 470°C, and the overall temperature upper limit value A is 540°C.
[0214] The lower limit of the bonding wire temperature corresponding to the first bonding wire D 1 The upper limit of the temperature of the first welding wire is 460℃. 1 It is 550℃.
[0215] The lower limit of the bonding wire temperature corresponding to the second bonding wire D 2The upper limit of the temperature of the second welding wire is 480℃. 2 It is 570℃.
[0216] The lower limit of the welding wire temperature corresponding to the third welding wire is D 3 The upper limit of the temperature of the third welding wire is 500℃. 3 It is 590℃.
[0217] The lower limit of the bonding wire temperature corresponding to the fourth bonding wire D 4 The upper limit of the temperature of the fourth welding wire is 520℃. 4 It is 590℃.
[0218] The abnormally high temperature threshold E is 600°C, and the abnormally high temperature point number threshold Z is 30.
[0219] The initial soldering temperature threshold F is 480°C.
[0220] The slope threshold K is 2.
[0221] Execute steps 101 and 102, and the present embodiment obtains Fig.10 The temperature profiles of all 24 wire bonds on the 6 bus bars are shown.
[0222] Next, step 103 is executed, that is, for each bus bar, the temperature curves of the four welding wires on the bus bar are analyzed to determine whether the welding quality of the bus bar is qualified.
[0223] The specific process is as follows:
[0224] Based on the surface temperature values contained in the temperature curves of the four welding wires on each busbar, the overall temperature average X of each busbar is calculated, see Table 5.
[0225] Among them: the temperature average value X of the first busbar is 501°C, the temperature average value X of the second busbar is 491°C, the temperature average value X of the third busbar is 482°C, the temperature average value X of the fourth busbar is 577°C, the temperature average value X of the fifth busbar is 495°C, and the temperature average value X of the sixth busbar is 490°C.
[0226] The overall temperature average values X of the 1st, 2nd, 3rd, 5th and 6th busbars are all between the overall temperature lower limit value B and the overall temperature upper limit value A (i.e., between 470°C and 540°C). Therefore, the welding quality of these busbars can be determined to be qualified.
[0227] The overall temperature average X of the 4th busbar is higher than the overall temperature upper limit A. Therefore, it is necessary to analyze the temperature curve of each welding line on the 4th busbar separately to further determine whether the welding quality of the 4th busbar is qualified. Specifically:
[0228] Calculate the average temperature X of each welding wire on the fourth busbar i , see Table 5, where the average wire temperature of the first wire is X 1 The average wire temperature of the second wire is 522℃. 2 The average wire temperature of the third wire is 593℃. 3 The average wire temperature of the fourth wire is 576℃. 4 It is 616℃.
[0229] The average temperature of the first welding wire is within the lower limit of the welding wire temperature D corresponding to the first welding wire. 1 The upper limit of the welding wire temperature corresponding to the first welding wire C 1 (i.e., between 460°C and 550°C), so the first welding wire can be determined as a qualified welding wire.
[0230] The average temperature of the third welding wire is within the lower limit of the welding wire temperature corresponding to the third welding wire D 3 The upper limit of the welding wire temperature corresponding to the third welding wire C 3 (i.e., between 500°C and 590°C), so the third welding wire can be determined as a qualified welding wire.
[0231] The average temperature of the second welding wire is greater than the upper limit of the welding wire temperature C corresponding to the second welding wire. 2 (i.e. 570°C).
[0232] The average temperature of the fourth welding wire is greater than the upper limit of the welding wire temperature C corresponding to the fourth welding wire. 4 (i.e. 590°C).
[0233] Therefore, it is necessary to perform further abnormal high temperature analysis on the second welding wire and the fourth welding wire to determine whether the second welding wire and the fourth welding wire are qualified welding wires or unqualified welding wires.
[0234] By performing abnormal high temperature analysis on the second and fourth welding wires, the following results were obtained, see Table 5:
[0235] In the temperature curve of the second welding wire, the number of surface temperature values higher than the abnormally high temperature threshold E is 29, which is less than the abnormally high temperature point number threshold Z. Therefore, the second welding wire can be determined as a qualified welding wire.
[0236] In the temperature curve of the fourth welding wire, the number of surface temperature values higher than the abnormally high temperature threshold E is 73, which is greater than the abnormally high temperature point number threshold Z. Therefore, the fourth welding wire can be determined as an unqualified welding wire.
[0237] In addition, in this embodiment, the fourth welding wire on the fourth busbar is subjected to unqualified attribution analysis, see Table 5, wherein: the starting welding temperature value of the fourth welding wire (the average value of the starting 10 surface temperature values on the temperature curve) is 513°C, which is greater than the starting welding temperature threshold F, so it can be determined that there is dirt on the surface of the busbar.
[0238] Because the fourth welding line is an edge welding line, when the judgment standard of a qualified bus bar is that the unqualified welding line cannot be located at the edge, the fourth bus bar is finally judged as an unqualified bus bar.
[0239] Table 5. Quality analysis results of the components of Example 5
[0240]
[0241] Example 6
[0242] Welding requirements: Weld three junction boxes to the photovoltaic module, where each junction box needs to be welded with two bus bars, that is, a total of 6 bus bars need to be welded. During the welding process, the laser scans each bus bar to form 3 welding lines, and finally a total of 18 welding lines are formed on a photovoltaic module.
[0243] The welding process parameters are: laser welding power 800W, welding speed of the first welding line 30mm / s, welding speed of the second welding line 33mm / s, and welding speed of the third welding line 38mm / s.
[0244] The preset judgment standard values are as follows:
[0245] The overall temperature lower limit value B is 480°C, and the overall temperature upper limit value A is 565°C.
[0246] The lower limit of the bonding wire temperature corresponding to the first bonding wire D 1 The lower limit of the temperature of the first welding wire is 460℃. 1 It is 560℃.
[0247] The lower limit of the bonding wire temperature corresponding to the second bonding wire D 2 The lower limit of the wire temperature corresponding to the second wire is 480℃. 2 It is 580℃.
[0248] The lower limit of the welding wire temperature corresponding to the third welding wire is D 3 The lower limit of the wire temperature corresponding to the third wire is 500℃. 3 It is 590℃.
[0249] The abnormally high temperature threshold E is 600°C, and the abnormally high temperature point number threshold Z is 20.
[0250] The initial soldering temperature threshold F is 480°C.
[0251] The slope threshold K is 2.
[0252] Execute steps 101 and 102, and the present embodiment obtains Fig.11 The temperature profiles of all 18 wire bonds on 6 bus bars are shown.
[0253] Next, step 103 is executed, that is, for each bus bar, the temperature curves of the three welding wires on the bus bar are analyzed to determine whether the welding quality of the bus bar is qualified.
[0254] The specific process is as follows:
[0255] Based on the surface temperature values contained in the temperature curves of the three welding wires on each busbar, the overall temperature average X of each busbar is calculated, see Table 6.
[0256] Among them: the temperature average value X of the first busbar is 507°C, the temperature average value X of the second busbar is 515°C, the temperature average value X of the third busbar is 525°C, the temperature average value X of the fourth busbar is 527°C, the temperature average value X of the fifth busbar is 595°C, and the temperature average value X of the sixth busbar is 542°C.
[0257] The overall temperature average values X of the 1st, 2nd, 3rd, 4th and 6th busbars are all between the overall temperature lower limit value B and the overall temperature upper limit value A (i.e., between 480°C and 565°C). Therefore, the welding quality of these busbars can be determined to be qualified.
[0258] The overall temperature average X of the 5th busbar is greater than the overall temperature upper limit A. Therefore, it is necessary to analyze the temperature curve of each welding line on the 5th busbar separately to further determine whether the welding quality of the 5th busbar is qualified. Specifically:
[0259] Calculate the average wire temperature X of each wire on the 5th busbar i , see Table 6, where the average temperature of the first welding wire is X 1 The average wire temperature of the second wire is 544℃. 2 The average wire temperature of the third wire is 604℃. 3 It is 637℃.
[0260] The average temperature of the first welding wire is within the lower limit of the welding wire temperature D corresponding to the first welding wire. 1 The upper limit of the welding wire temperature corresponding to the first welding wire C 1 (i.e., between 460°C and 560°C), so the first welding wire can be determined as a qualified welding wire.
[0261] The average temperature of the second welding wire is greater than the upper limit of the welding wire temperature C corresponding to the second welding wire. 2 (i.e. 580°C).
[0262] The average temperature of the third welding wire is greater than the upper limit of the welding wire temperature C corresponding to the third welding wire. 3 (i.e. 590°C).
[0263] Therefore, it is necessary to perform further abnormal high temperature analysis on the second welding wire and the third welding wire to determine whether the second welding wire and the third welding wire are qualified welding wires or unqualified welding wires.
[0264] By performing abnormal high temperature analysis on the second and third welding wires, the following results were obtained, see Table 6:
[0265] In the temperature curve of the second welding wire, the number of surface temperature values higher than the abnormally high temperature threshold E is 10, which is less than the abnormally high temperature point number threshold Z, so the second welding wire can be determined as a qualified welding wire.
[0266] In the temperature curve of the third welding wire, the number of surface temperature values higher than the abnormally high temperature threshold E is 27, which is greater than the abnormally high temperature point number threshold Z. Therefore, the third welding wire can be determined as an unqualified welding wire.
[0267] Because the third welding line is an edge welding line, and the criterion for determining a qualified bus bar is that an unqualified welding line cannot be located at the edge, the fifth bus bar is ultimately determined to be an unqualified bus bar.
[0268] In addition, in this embodiment, the second and third welding wires on the fifth bus bar are analyzed for unqualified reasons, as shown in Table 6, where:
[0269] The starting welding temperature value of the third welding wire (the average value of the starting 10 surface temperature values on the temperature curve) is 495° C., which is greater than the starting welding temperature threshold F. Therefore, it can be determined that there is dirt on the busbar surface.
[0270] The slope values of the second and third welding wires are 2.89 and 3.22 respectively, both of which are greater than the slope threshold K. Therefore, it can be determined that there is a gap between the busbar and the junction box.
[0271] Table 6. Quality analysis results of the components of Example 6
[0272]
[0273] The present application also provides a busbar laser welding quality detection device, which includes a memory and a processor, wherein the memory stores at least one program instruction, and the processor implements the busbar laser welding quality detection method in any of the above embodiments by loading and executing at least one program instruction.
[0274] The present application also provides a computer storage medium, in which at least one program instruction is stored, and the at least one program instruction is loaded and executed by a processor to implement the busbar laser welding quality detection method in any of the above embodiments.
[0275] The present application is described in sufficient detail above with certain particularity. It should be understood by those skilled in the art that the description in the embodiments is merely exemplary, and all changes made without departing from the true spirit and scope of the present application should fall within the scope of protection of the present application. The scope of protection claimed in the present application is defined by the claims, rather than by the above description in the embodiments.
Claims
1. A busbar laser welding quality detection method, characterized in that: The busbar laser welding quality detection method is used to detect the welding quality of the busbar and the junction box after laser welding. The laser scans and welds on a busbar to form N welding lines, where N is greater than 1. The busbar laser welding quality detection method includes: During the welding process of each welding wire, the surface temperature value of the welding part is collected at predetermined time intervals; Based on the collected surface temperature values, fitting a temperature curve of the surface temperature value of each welding wire changing with time; For each bus bar, the temperature curves of the N welding wires on the bus bar are analyzed to determine whether the welding quality of the bus bar is qualified.
2. The busbar laser welding quality inspection method according to claim 1, characterized in that: The step of analyzing the temperature curves of the N welding wires on the bus bar to determine whether the welding quality of the bus bar is qualified includes: Calculating an overall temperature average X of the N welding wires on the bus bar based on the surface temperature values included in the temperature curves of the N welding wires on the bus bar; If B≤X≤A, the welding quality of the busbar is determined to be qualified, wherein B is a preset lower limit value of the overall temperature, and A is a preset upper limit value of the overall temperature; If X<B, it is determined that the welding quality of the busbar is unqualified; If X>A, the temperature curve of each welding line on the bus bar is analyzed separately to determine whether the welding quality of the bus bar is qualified.
3. The busbar laser welding quality inspection method according to claim 2, characterized in that: The determining whether the welding quality of the busbar is qualified by individually analyzing the temperature curve of each welding wire on the busbar includes: Analyzing the temperature curve of each welding wire on the bus bar individually to determine whether each welding wire is a qualified welding wire or an unqualified welding wire; Whether the welding quality of the busbar is qualified is determined according to the information of the unqualified welding wire.
4. The busbar laser welding quality inspection method according to claim 3, characterized in that: The separately analyzing the temperature curve of each welding wire on the bus bar to determine whether each welding wire is a qualified welding wire or an unqualified welding wire includes: Based on the surface temperature value included in the temperature curve of the i-th welding wire on the bus bar, the average welding wire temperature X of the i-th welding wire on the bus bar is calculated. i , 1≤i≤N; If D i ≤X i ≤C i , determine the i-th bonding wire as a qualified bonding wire, wherein the D i is the preset lower limit of the welding wire temperature corresponding to the i-th welding wire in each busbar, C i is the preset upper limit value of the welding wire temperature suitable for the i-th welding wire in each busbar; If X i <D i , determining that the i-th welding wire on the busbar is an unqualified welding wire; If X i >C i , an abnormal high temperature analysis is performed on the i-th welding wire based on the temperature curve of the i-th welding wire on the bus bar to determine whether the i-th welding wire is a qualified welding wire or an unqualified welding wire.
5. The busbar laser welding quality inspection method according to claim 3, characterized in that: The separately analyzing the temperature curve of each welding wire on the bus bar to determine whether each welding wire is a qualified welding wire or an unqualified welding wire includes: Based on the surface temperature value included in the temperature curve of the i-th welding wire on the bus bar, the average welding wire temperature X of the i-th welding wire on the bus bar is calculated. i , 1≤i≤N; If D≤X i ≤C, the i-th welding wire is determined to be a qualified welding wire, wherein D is a preset lower limit value of the welding wire temperature, and C is a preset upper limit value of the welding wire temperature; If X i <D, the i-th welding wire on the busbar is determined to be an unqualified welding wire; If X i >C, an abnormal high temperature analysis is performed on the i-th welding wire based on the temperature curve of the i-th welding wire on the bus bar to determine whether the i-th welding wire is a qualified welding wire or an unqualified welding wire.
6. The busbar laser welding quality inspection method according to claim 4 or 5, characterized in that: The performing abnormal high temperature analysis on the i-th welding wire based on the temperature curve of the i-th welding wire on the bus bar to determine whether the i-th welding wire is a qualified welding wire or an unqualified welding wire includes: Count the number of surface temperature values higher than an abnormally high temperature threshold E among the surface temperature values included in the temperature curve of the i-th welding wire on the busbar, wherein the abnormally high temperature threshold E is greater than the welding wire temperature upper limit C i Or the upper limit of the welding wire temperature C; If the number of surface temperature values higher than the abnormally high temperature threshold value E is greater than the abnormally high temperature point number threshold value Z, the i-th welding wire is determined to be an unqualified welding wire; If the number of surface temperature values higher than the abnormally high temperature threshold value E is not greater than the abnormally high temperature point number threshold value Z, the i-th welding wire is determined to be a qualified welding wire.
7. The busbar laser welding quality inspection method according to claim 3, characterized in that: The information of the unqualified welding wires includes the number and position of the unqualified welding wires, and determining whether the welding quality of the busbar is qualified according to the information of the unqualified welding wires includes: Determining whether the welding quality of the busbar is qualified according to the number of unqualified welding lines; or, Whether the welding quality of the busbar is qualified is determined according to the number and positions of the unqualified welding lines.
8. The busbar laser welding quality inspection method according to claim 3, characterized in that: After determining that each welding line is a qualified welding line or an unqualified welding line, the busbar laser welding quality detection method further includes: At least an attribution analysis is performed on the unqualified welding wires on the bus bar to determine the reasons causing the welding wires or the bus bar to be unqualified.
9. The busbar laser welding quality inspection method according to claim 8, characterized in that: The attribution analysis of at least the unqualified welding wire on the bus bar to determine the cause of the unqualified welding wire or bus bar includes: Calculating the starting welding temperature value and / or the slope of the temperature curve of each unqualified welding wire in the busbar, or calculating the starting welding temperature value and / or the slope of the temperature curve of each unqualified welding wire and qualified welding wire in the busbar, wherein the starting welding temperature value is the average of the first M surface temperature values in the temperature curve of the welding wire; If the starting welding temperature value is greater than the starting welding temperature threshold F, it is determined that the reason for the failure of the welding wire or bus bar is that the bus bar surface is dirty; If the slope of the temperature curve of the welding wire is greater than the slope threshold value K, it is determined that the reason for the failure of the welding wire or the bus bar is a gap between the bus bar and the junction box.
10. The busbar laser welding quality inspection method according to claim 1, characterized in that: The collecting of the surface temperature value of the welding part at every predetermined time interval comprises: At predetermined time intervals, the intensity of the thermal radiation light radiated from the welding position is collected by an infrared temperature measuring device.
11. A busbar laser welding quality inspection device, characterized in that: The busbar laser welding quality detection device includes a memory and a processor, wherein the memory stores at least one program instruction, and the processor implements the busbar laser welding quality detection method according to any one of claims 1 to 10 by loading and executing at least one program instruction.
12. A computer storage medium, characterized in that: At least one program instruction is stored in the computer storage medium, and at least one program instruction is loaded and executed by the processor to implement the busbar laser welding quality detection method according to any one of claims 1 to 10.
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CN121049340A