Automatic welding system and method for battery cell pole column module

Abstract

According to the automatic welding system and method for the battery cell pole column module, center point information of a pole column is collected through an image collecting module, analyzed, processed and fed back to a single spot welding machine so as to be used for adjusting the position of a welding gun of the single spot welding machine. And through the welding track curve, the welding strength of the product is improved. The method not only perfectly adapts to an automatic production line, but also improves the welding speed and precision of the battery cell in the module, improves the production efficiency of the module in the production line, enhances the welding stability and firmness of the battery cell, reduces the production cost, and is compatible with welding of modules of various models.

Description

Technical Field

[0001] The present invention relates to the technical field of battery processing, and in particular to an automated welding system and method for a battery cell pole module. Background Art

[0002] With the rapid development of power battery technology in the new energy field around the world, all fields are trying to transform towards new energy power as much as possible, which has brought large-scale production demands for power batteries. There are a wide variety of power batteries on the market, meeting the increasing diverse needs of products. Such a large-scale product demand necessarily requires large production lines to support, for more efficient and rapid production of power batteries. Therefore, intelligent device welding technology has become an essential part of the automated workshop, used to quickly weld countless module battery cells, welding each cell pole together through aluminum bars to achieve series and parallel connections between the battery cells in the module. The common automated welding methods for current battery cells and aluminum bars on the market mainly involve arranging square-shell or cylindrical battery cells in a modular manner, and then using manual or automatic welding equipment to melt the aluminum bars with lasers and weld the cell poles and the aluminum bars on the poles together.

[0003] The prior art invention patent with the publication number CN112935473B discloses an automatic welding machine based on machine vision and its control method, mainly providing an automatic welding machine based on machine vision, including a welding current control module for controlling the welding current; a welding speed control module for controlling the welding speed; a welding torch height control module for controlling the welding arc length; a weld seam image acquisition module for taking weld seam images; a weld seam image storage module for pre-storing standard weld seam images and storing the images taken by the weld seam image acquisition module; a weld seam image analysis module for analyzing the weld seam images taken by the weld seam image acquisition module; and a welding machine control module, communicatively connected to the welding current control module, the welding speed control module, and the welding torch height control module, for controlling the welding parameters according to the analysis results of the weld seam image analysis module. The present invention can improve the deficiencies of the prior art and increase the speed of weld seam quality detection. Summary of the Invention

[0004] In the prior art, manual positioning of battery cells and long-term manual holding of welding torches for welding are commonly used. This welding method has problems such as high labor intensity, low welding efficiency, and poor welding accuracy during the welding process. Batch welding with an automatic welding device without compensation. In this welding method, due to the inevitable errors between battery cells and the fact that the device can only achieve preset fixed-point position welding, the position of the welding point cannot be adjusted according to the errors of the battery cells, resulting in poor welding accuracy, insecure welding, or even false soldering and missed soldering. When welding through a detection and positioning tooling or image acquisition and vision guidance, it relies on a stable compensation algorithm and calibration mechanism, and the welding efficiency is relatively low. Or using a dedicated automated welding device, when switching the module model for welding, problems such as difficult switching of programs, troublesome replacement of module positioning tooling, and cumbersome debugging of welding parameters are often encountered.

[0005] To solve the above problems, the technical solution provided by the present invention is: an automated welding method for a battery cell pole module, characterized by comprising the following steps: S1. Determine the theoretical coordinates of the center points of each pole according to the battery cell pole module model; S2. The image acquisition module acquires the actual positions of the center points of each battery cell pole to obtain coordinate error compensation; S3. The laser emitting head locates the welding points according to the theoretical coordinates and the coordinate error compensation for automated welding.

[0006] Specifically, the image acquisition module directly acquires the center points of the battery cell poles using a vision sensor. Through the acquired images, the gray levels are compared between each pixel, and the deviation points are filtered out by the noise reduction algorithm using the gray level difference, and the entire circle and its center are calculated to obtain the actual pole center points. The position differences are calculated respectively between all the acquired pole center points and all the theoretical center points, and then this difference is used to compensate the accuracy of the welding points respectively.

[0007] Specifically, the welding trajectory curve of a single welding point in S3 is a spiral line formed by the alienation of a circular bus with the welding point as the center.

[0008] Specifically, during welding, the moving speed of the welding torch is fixed. The penetration depth of the welding point is controlled by changing the spiral pitch of the spiral line, and the width of the welding point is controlled by changing the spiral radius of the spiral line.

[0009] Specifically, during the welding process, the welding cycle of a single welding point is divided into a start end, a working section, and an end. During the start end, the power of the welding laser beam linearly rises from 0, remains unchanged during the working section, and linearly decreases to 0 at the same rate as the start end during the end.

[0010] Specifically, it is characterized in that the welding trajectories of the start end and the end coincide, so that the welding effect of the overlapping part of the welding trajectory is the same as that of the welding trajectory of the working section.

[0011] The present invention provides an automated welding system for a battery cell pole module, which uses the above-mentioned automated welding method for the battery cell pole module, and includes a spot welder. A first slide rail is provided on the base of the spot welder, and a fixed fixture is provided on the first slide rail. The battery cell module is fixed by the fixed fixture.

[0012] Specifically, the battery cell module includes a module housing in the shape of a lidless box. The battery cells are arranged and fixed in the module housing in groups, and the pole center points of the battery cell poles are exposed on the upper surfaces of the battery cells. A battery cell support is provided on the battery cells, and the aluminum busbar is fixed on the battery cell poles by the battery cell support. The through holes of the aluminum busbar correspond to the positions of the pole center points.

[0013] Specifically, on the base of the spot welder, except for one side of the first slide rail, vertical walls are provided on the other three sides. A set of Y-axis slide rails are provided on the opposite two vertical walls, an X-axis slide rail is bridged on the Y-axis slide rails, a fixed seat is provided on the X-axis slide rail, a Z-axis slider is provided on the fixed seat, tracks are provided on both sides of the Z-axis slider, and the Z-axis slider slides up and down through the tracks; an image acquisition module is provided on the side of the Z-axis slider, and a laser emitter is provided at the bottom. An aluminum busbar pressing mechanism is provided at the lower end of the laser emitter.

[0014] Specifically, the fixed fixture is provided with a square bottom plate, and uniformly distributed mounting holes are provided on the bottom plate. Fixed edges are provided on two adjacent sides of the bottom plate, and the fixed edges are fixed through the mounting holes; two clamping frames are further provided on the bottom plate, and clamping fixtures are provided on the clamping frames; the clamping frames change the mounting positions through the mounting holes, and different-sized battery cell modules are fixed through the clamping fixtures.

[0015] The beneficial effects of the present invention are as follows: By collecting the actual coordinates and theoretical coordinates of the pole center points to calculate the error compensation, the accuracy of the automated welding with precision compensation is ensured, and visual image determination of the position is not required during welding, resulting in higher efficiency; By changing the welding trajectory parameters to adjust the penetration depth and width of the weld spots, it is convenient for welding different battery cell modules; The transformable design of the fixed fixture facilitates the loading, unloading, and replacement of different models of battery cell modules for welding; By controlling the laser output time and power at the beginning and end of welding, the beginning and end of the welding trajectory are made to coincide, ensuring the integrity of the welding process within each welding cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0017] Figure 2 It is a schematic diagram of the structure of the fixed fixture of the present invention.

[0018] Figure 3 It is a schematic diagram of the structure of the battery cell module of the present invention.

[0019] Figure 4 It is a schematic diagram of the structure of the spot welder of the present invention.

[0020] Figure 5This is the welding output power curve of the present invention.

[0021] Figure 6 This is a schematic diagram of the welding track of the present invention.

[0022] In the figure, 1 is a spot welder, 2 is a fixed fixture, 3 is a battery cell module, 21 is a bottom plate, 22 is a first fixed edge, 23 is a first clamping frame, 24 is a second fixed edge, 25 is a second clamping frame, 211 is a mounting hole, 31 is an aluminum busbar, 32 is a battery cell bracket, 33 is a battery cell, 34 is a module housing, 311 is a through hole, 331 is the center point of the pole, 11 is a first slide rail, 12 is an aluminum busbar pressing mechanism, 13 is a laser emitting head, and 14 is an image acquisition module. Specific embodiments

[0023] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0024] Traditional battery cell welding technologies generally fall into the following categories.

[0025] First, manually position the battery cells and manually hold the welding torch for a long time for welding. In this welding method, there are problems such as high labor intensity, low welding efficiency, and poor welding accuracy during the welding process; Second, batch welding is performed by an automatic welding device without compensation. In this welding method, due to the inevitable errors between battery cells and the fact that the device can only perform welding at preset fixed-point positions, the position of the welding point cannot be adjusted according to the errors of the battery cells, resulting in poor welding accuracy, insecure welding, or even false welding and missed welding; Third, welding with compensation is performed by detecting the positioning tooling or detecting the dimensional errors of the battery cell housing. This welding method usually uses a detection device specifically for detecting the dimensional errors of the battery cell housing to collect the errors, and then compensates for the welding point errors through an adjustment component for adjusting the position of the battery cell to be welded or an adjustment mechanism for adjusting the position of the welding torch mechanism. This method only compensates for the external shape errors between battery cells and does not solve the problem of compensating for the position errors of the battery cell poles relative to their own housings in each battery cell. And before each welding point is welded, the position error of this welding point needs to be detected and compensated, so the welding efficiency is relatively low, and there are accuracy errors in the adjustment mechanism or component itself; 4. It is to use vision-guided welding. In this welding method, an image acquisition device is used to capture the image of the solder joint position. After algorithm processing, a set of solder joint coordinates is generated, and then the welding path is automatically generated. Finally, the position of the solder joint is controlled by adjusting the angle of the laser emission lens. This method relies on a stable compensation algorithm. Automatically generating the welding path requires not only algorithm support, but also a large amount of welding data for analysis. A large amount of experimental time and times are required to iteratively optimize the parameters, and it is impossible to adjust the Z-axis height direction, the distance between the pole column and the welding torch, and the welding torch. In addition, the equipment used in this method is extremely expensive; 5. It is to adopt a dedicated automated welding device. This method can meet the requirements of pipeline production. However, when switching the module model for welding, problems such as difficult switching of programs, troublesome replacement of module positioning tooling, and cumbersome debugging of welding parameters are often encountered.

[0026] In view of the above comprehensive considerations, the present invention aims to provide a new welding method for the pole column of the battery cell and the aluminum row, that is, the visual recognition module is used to assist the single-point welder to weld the pole column of the battery cell in the module. The image acquisition module collects the information of the center point of the pole column, analyzes and processes it, and feeds it back to the single-point welder to adjust the position of the welding torch of the single-point welder. And through the welding trajectory curve in the present invention, the welding strength of the product is improved. This method not only perfectly adapts to the automatic production line, but also improves the welding speed and accuracy of the battery cell in the module, improves the production efficiency of the module in the production line, strengthens the welding stability and firmness of the battery cell, reduces the production cost, is compatible with the welding of multiple models of modules, and does not require changing the equipment and welding parameters when adjusting the production product. Only need to input the welding position of the first solder joint of the new model module, and list the positions of the remaining solder joints based on this; or directly open the module model file configured before, and the automatic welding of all modules of this model can be realized, and the error is automatically compensated during the welding process.

[0027] Embodiment 1: An automated welding method for the pole column module of a battery cell, characterized by including the following steps: S1. Determine the theoretical coordinates of the center points of each pole column according to the model of the pole column module of the battery cell; S2. The image acquisition module collects the actual positions of the center points of each battery cell pole column to obtain coordinate error compensation; S3. The laser emission head locates the solder joint according to the theoretical coordinates and the coordinate error compensation, and performs automated welding.

[0028] The image acquisition module 14 directly collects the position of the center point 331 of the battery cell pole column by using a vision sensor. Through the collected image, the gray level comparison is performed between each pixel, and the deviation points are filtered out by the noise reduction algorithm using the gray level difference value, and the whole circle and its center are calculated to obtain the actual center point of the pole column. The position differences are respectively made between all the collected center points of the pole columns and all the theoretical center points, and then this difference is used to perform precision compensation on the solder joints respectively.

[0029] The welding trajectory curve of the single solder joint in S3 is a spiral line formed by the alienation of a circular bus with the solder joint as the center of the circle.

[0030] During welding, the moving speed of the welding torch is fixed. The penetration depth of the solder joint is controlled by changing the spiral pitch of the spiral line, and the width of the solder joint is controlled by changing the spiral radius of the spiral line.

[0031] During the welding process, the welding cycle of a single solder joint is divided into a starting end, a working section, and an ending end. During the starting end, the power of the welding laser beam linearly increases from 0. During the working section, the power of the welding laser beam remains unchanged. During the ending end, the power of the laser beam linearly decreases to 0 at the same rate as the starting end.

[0032] It is characterized in that the welding trajectories of the starting end and the ending end coincide, so that the welding effect of the overlapping part of the welding trajectory is the same as that of the welding trajectory of the working section.

[0033] The present invention provides an automatic welding system for a battery cell pole module, which uses the above-mentioned automatic welding method for a battery cell pole module. It includes a single-point welding machine 1. A first slide rail 11 is provided on the base of the single-point welding machine 1, and a fixed fixture 2 is provided on the first slide rail 11. The battery cell module 3 is fixed by the fixed fixture 2.

[0034] The battery cell module 3 includes a module housing 34 in the shape of an uncovered box. The battery cells are arranged and fixed in the module housing 34, and the center points 331 of the pole columns of the battery cell poles are exposed on the upper surface of the battery cells; a battery cell support 32 is provided on the battery cells, and the battery cell support 32 fixes the aluminum row 31 on the battery cell poles. The through hole 311 of the aluminum row 31 corresponds to the position of the center point 331 of the pole column.

[0035] On the base of the single-point welding machine 1, except for one side of the first slide rail 11, vertical walls are provided on the other three sides. A set of Y-axis slide rails are provided on the opposite two vertical walls. An X-axis slide rail is bridged on the Y-axis slide rails. A fixed seat is provided on the X-axis slide rail, and a Z-axis slider is provided on the fixed seat. Tracks are provided on both sides of the Z-axis slider, and the Z-axis slider slides up and down through the tracks; an image acquisition module 14 is provided on the side of the Z-axis slider, and a laser emission head 13 is provided at the bottom. An aluminum row pressing mechanism 12 is provided at the lower end of the laser emission head 13. Springs and limits are provided on the aluminum row pressing mechanism 12, so that it can only move in the Z-axis direction, thereby pressing the aluminum row 31 on the upper surface of the battery cell pole to be welded and realizing the adjustment of the Z-axis height of the welding torch. The X-axis slide rail can slide on the Y-axis slide rail to realize the Y-axis positioning of the laser emission head 13; the Z-axis slider slides on the X-axis slide rail to realize the X-axis positioning of the laser emission head 13. The aluminum row pressing mechanism 12 controls the up and down sliding of the Z-axis slider to realize the adjustment of the Z-axis height of the welding torch.

[0036] The fixed fixture 2 is provided with a square base plate 21. The base plate 21 is provided with evenly distributed mounting holes 211. On two adjacent sides of the base plate 21, a first fixed edge 22 and a second fixed edge 24 are respectively provided. The fixed edges are fixed through the mounting holes 211. The base plate 21 is further provided with a first clamping frame 23 and a second clamping frame 25. Clamping fixtures are provided on the clamping frames. The clamping frames change the mounting positions through the mounting holes 211 and fix the battery cell modules 3 of different sizes through the clamping fixtures.

[0037] During use, the accuracy compensation measures for the welding points are as follows: On the XY plane, assume the distance between the center point of the image acquisition module 14 and the laser emitting head 13 in the X direction is L, and the distance in the Y direction is 0. By teaching or coordinate input, the model number of the module to be welded is determined. The center point of the first pole of this model of module is used as the Mark point, and its coordinates are (x1, y1), the center point of the second pole is (x2, y2),..., and the center point of the nth pole is (xn, yn). This is the theoretical value of the welding position without error. However, due to errors in the center points of the battery cell poles in the module and the positioning tooling. When welding the remaining modules, first, the image acquisition module 14 is used to collect the position information of the center point of each pole. Taking the theoretical coordinates (xn, yn) as the origin, the relative coordinates of the image acquisition position of the center point of the first pole 331 of the remaining modules are (a1, b1), the relative coordinates of the image acquisition position of the center point of the second pole are (a2, b2),..., and the relative coordinates of the image acquisition position of the center point of the nth pole are (an, bn). (an, bn) is the error between the center point of each pole and the theoretical coordinates. Then, the absolute coordinates of each actual welding point in this package of battery cell modules are obtained as (X, Y). Among them: (X, Y) = (xn + an + L, yn + bn + 0). When all the actual welding point coordinates are gathered together, a coordinate set is obtained: (X1, Y1), (X2, Y2),...,(Xn, Yn). This coordinate set is all the welding positions of the current single package of modules to be processed.

[0038] During welding, the welding trajectory of a single welding point is actually a spiral line derived by taking the center of the through hole 311 on the aluminum row 31 as the center and using a circular curve as the generatrix. Setting the welding trajectory as a spiral line can more conveniently control the curve parameters, thereby realizing the control of the weld width and weld depth of the welding point. Since during the welding process, the laser beam used by the welding torch at the welding start end and the welding end cannot achieve immediate full-power output and immediate termination of output, the welding process within a single welding point is recorded as a welding cycle. As Figure 5 shown, each welding cycle is divided into a start end, a working section, and an end. The laser output power within the working section is constant. The output power at the start end is set to increase linearly, and the output power at the end is set to decrease linearly. By making the welding trajectories at the start end and the end coincide, the welding effects at the start end and the end can be made consistent with the welding effect in the working section.

[0039] Embodiment 2: An automatic welding method for a battery cell pole module, characterized by comprising the following steps: S1. Determine the theoretical coordinates of the center points of each pole according to the model of the battery cell pole module; S2. The image acquisition module acquires the actual positions of the center points of each battery cell pole to obtain coordinate error compensation; S3. The laser emitting head locates the welding points according to the theoretical coordinates and the coordinate error compensation for automatic welding.

[0040] The image acquisition module 14 directly acquires the position of the center point 331 of the battery cell pole by using a vision sensor. Through the acquired image, the gray levels are compared between each pixel, the deviation points are filtered out by a noise reduction algorithm using the gray level difference, and the whole circle and its center are calculated to obtain the actual pole center point. The position differences are respectively made between all the acquired pole center points and all the theoretical center points, and then this difference is used to perform precision compensation on the welding points respectively.

[0041] In S3, the welding trajectory curve of a single welding point is a spiral line formed by the alienation of a circular bus with the welding point as the center.

[0042] During welding, the moving speed of the welding torch is fixed. The penetration depth of the welding point is controlled by changing the spiral pitch of the spiral line, and the width of the welding point is controlled by changing the spiral radius of the spiral line.

[0043] During the welding process, the welding cycle of a single welding point is divided into a starting end, a working section, and an ending end. In the starting end, the power of the welding laser beam linearly rises from 0, in the working section, the power of the welding laser beam remains unchanged, and in the ending end, the power of the laser beam linearly decreases to 0 at the same rate as the starting end.

[0044] It is characterized in that the welding trajectories of the starting end and the ending end coincide, so that the welding effect of the overlapping part of the welding trajectory is the same as that of the welding trajectory of the working section.

[0045] The present invention provides an automatic welding system for a battery cell pole module, which uses the above-mentioned automatic welding method for a battery cell pole module. As Figure 1 shown, it includes a single-point welder 1. A first slide rail 11 is provided on the base of the single-point welder 1, and a fixed fixture 2 is provided on the first slide rail 11. The battery cell module 3 is fixed by the fixed fixture 2. The fixed fixture 2 can drive the battery cell module 3 to slide on the first slide rail 11, facilitating the disassembly and installation of the battery cell module 3 by construction personnel.

[0046] As Figure 3 shown, the battery cell module 3 includes a module housing 34 of a lidless box type. The battery cells are arranged and fixed in the module housing 34, and the center points 331 of the poles of the battery cell poles are exposed on the upper surface of the battery cells; a battery cell support 32 is provided on the battery cells, and the aluminum row 31 is fixed on the battery cell poles by the battery cell support 32. The through holes 311 of the aluminum row 31 correspond to the positions of the center points 331.

[0047] As Figure 4 shown, on the base of the spot welder 1, except for one side of the first slide rail 11, vertical walls are provided on the other three sides. A set of Y-axis slide rails are provided on the opposite two vertical walls. The X-axis slide rail straddles the Y-axis slide rails. A fixed seat is provided on the X-axis slide rail. A Z-axis slider is provided on the fixed seat. Tracks are provided on both sides of the Z-axis slider. The Z-axis slider slides up and down through the tracks; an image acquisition module 14 is provided on the side of the Z-axis slider, and a laser emitter 13 is provided at the bottom. An aluminum row pressing mechanism 12 is provided at the lower end of the laser emitter 13. Springs and limits are provided on the aluminum row pressing mechanism 12 so that it can only move in the Z-axis direction, thereby pressing the aluminum row 31 against the upper surface of the electrode post to be welded of the battery cell and realizing the adjustment of the Z-axis height of the welding torch. The X-axis slide rail can slide on the Y-axis slide rails to realize the Y-axis positioning of the laser emitter 13; the Z-axis slider slides on the X-axis slide rail to realize the X-axis positioning of the laser emitter 13. The aluminum row pressing mechanism 12 controls the up and down sliding of the Z-axis slider to realize the adjustment of the Z-axis height of the welding torch.

[0048] As Figure 2 shown, the fixed fixture 2 is provided with a square bottom plate 21. Uniformly distributed mounting holes 211 are provided on the bottom plate 21. Fixed edges are provided on two adjacent sides of the bottom plate 21, and the fixed edges are fixed through the mounting holes 211; two clamping frames are further provided on the bottom plate 21, and clamping fixtures are provided on the clamping frames; the clamping frames change the mounting positions through the mounting holes 211 and fix battery cell modules 3 of different sizes through the clamping fixtures.

[0049] During use, the precision compensation measures for the welding points are as follows: On the XY plane, let the distance between the center points of the image acquisition module 14 and the laser emitting head 13 in the X direction be L, and the distance in the Y direction be 0. By teaching or coordinate input, the model number of the module to be welded is determined. The center point of the first pole of this model of module is used as the Mark point, and its coordinates are (x1, y1), the center point of the second pole 331 is (x2, y2),..., the center point of the nth pole 331 is (xn, yn). This is the theoretical value of the welding position without error. However, due to errors in the center points of each battery cell pole in the module and the positioning tooling. When welding the remaining modules, first, the image acquisition module 14 is used to collect the position information of the center point of each pole. Taking the theoretical coordinates (xn, yn) as the origin, the relative coordinates of the image acquisition position of the center point of the first pole 331 of the remaining modules are (a1, b1), the relative coordinates of the image acquisition position of the center point of the second pole are (a2, b2),..., the relative coordinates of the image acquisition position of the center point of the nth pole are (an, bn). (an, bn) is the error between the center point of each pole and the theoretical coordinates. Thus, the absolute coordinates of each actual welding point in this pack of battery cell modules 3 are obtained as (X, Y). Where: (X, Y) = (xn + an + L, yn + bn + 0). When all the coordinates of the actual welding points are gathered together, a coordinate set is obtained: (X1, Y1), (X2, Y2),...,(Xn, Yn). This coordinate set is all the welding positions of the current single-pack module to be processed.

[0050] In this embodiment, the single-point welder 1 can be modified into a multi-point welder. On the multi-point welder, to ensure work efficiency, the image acquisition module 14 and the laser emitting head 13 are placed separately. Taking the center point of the first pole of each pack of modules as the Mark point, when the image acquisition module 14 collects the position information of the center point of each pole, the laser welding module can only identify the Mark point of the previous pack of modules and read the collected position information to achieve automatic welding.

[0051] During welding, the welding trajectory of a single welding point is actually a spiral line derived from a circular curve with the center of the through hole 311 on the aluminum row 31 as the center. Setting the welding trajectory as a spiral line can more conveniently control the curve parameters, thereby achieving the control of the weld width and weld depth of the welding point. Since during the welding process, the laser beam used by the welding torch at the welding start end and the welding end cannot achieve full-power output immediately and terminate output immediately, the welding process within a single welding point is recorded as a welding cycle. Each welding cycle is divided into a start end, a working section, and an end. The laser output power within the working section is constant, the output power at the start end is set to increase linearly, and the output power at the end is set to decrease linearly. By overlapping the welding trajectories at the start end and the end, the welding effects at the start end and the end can be made consistent with the welding effect in the working section.

[0052] Figure 6 It is a schematic curve diagram of a welding track. Wherein R is the radius of the generatrix, and the size of the welding spot can be changed by adjusting the radius of the generatrix. The starting angle of the generatrix is regarded as the starting point of a single welding cycle, and the ending angle is regarded as the ending point of the welding cycle. By adjusting the included angle θ (θ > 360°) between the ending angle and the starting angle, the coincidence of the starting and ending welding tracks within the welding cycle can be ensured. P is the pitch of the helix obtained after the generatrix is distorted. Since the moving speed v of the welding gun of the single-point welder 1 is fixed, changing the pitch P of the helix can change the length d of the track curve per unit area of the aluminum row 31. It can be obtained that within the unit area, the residence time t of the welding gun = d / v. As the length of the welding track per unit area changes and the moving speed of the welding gun remains unchanged, the residence time t of the welding gun on the aluminum row 31 per unit area will change accordingly. With the power of the welding gun remaining unchanged, according to: total work W = time t × power Q, it can be obtained that within the unit area of the aluminum row 31, the total work done by the welding gun on the aluminum row 31 changes with the change of the residence time t, and the total work W received by the aluminum row 31 is proportional to the penetration depth at the welding spot. Therefore, changing the pitch P of the helix can change the penetration depth of the aluminum row 31. r is the helix radius of the helix, and changing the helix radius r can change the weld width at the welding spot.

[0053] Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An automatic welding method for a battery cell pole module, characterized in that: The following steps are involved: S1. Determine the theoretical coordinates of the center points of each pole according to the battery pole module model; S2, the image acquisition module collects the actual position of the center point of each battery cell pole to obtain coordinate error compensation; S3. The laser transmitter locates the welding point according to the theoretical coordinates and coordinate error compensation, and performs automatic welding.

2. The automatic welding method for battery cell pole module according to claim 1, characterized in that: The image acquisition module uses a visual sensor to directly capture the center point of the battery cell pole. Through the captured image, the grayscale comparison is performed between each pixel, and the deviation points are filtered out through the grayscale difference through the noise reduction algorithm. The whole circle and its center are calculated to obtain the actual pole center point. The position difference is made between all the collected pole center points and all the theoretical center points, and this difference is used to compensate the accuracy of the welding points.

3. The automatic welding method for battery cell pole module according to claim 1, characterized in that: The welding trajectory curve of a single welding point in S3 is a spiral line formed by the alienation of a circular generatrix with the welding point as the center.

4. The automatic welding method for battery cell pole module according to claim 1 or 3, characterized in that: During welding, the moving speed of the welding gun is fixed. The melting depth of the weld spot is controlled by changing the spiral pitch of the spiral line, and the melting width of the weld spot is controlled by changing the spiral radius of the spiral line.

5. The automatic welding method for battery cell pole module according to claim 1, characterized in that: The welding cycle of a single weld point during the welding process is divided into the beginning, the working section and the end. The welding laser beam power at the beginning increases linearly from 0, the welding laser beam power in the working section remains unchanged, and the laser beam power at the end decreases linearly to 0 at the same rate as the beginning.

6. The automatic welding method for battery cell pole module according to claim 1 or 5, characterized in that: The welding trajectories at the start and end are overlapped, so that the welding effect of the overlapping welding trajectory is consistent with the welding trajectory of the working section.

7. An automatic welding system for a battery cell pole module, using the automatic welding method for a battery cell pole module according to any one of claims 1 to 6, characterized in that: It comprises a single spot welding machine. A first slide rail is arranged on the base of the single spot welding machine. A fixing clamp is arranged on the first slide rail. The battery core module is fixed by the fixing clamp.

8. The automatic welding system for battery cell pole modules according to claim 7, characterized in that: The battery cell module includes a module shell of a coverless box type, the battery cells are arranged in groups and fixed in the module shell, and the pole center points of the battery cells are exposed on the upper surfaces of the battery cells; a battery cell bracket is provided on the battery cell, and the battery cell bracket fixes the aluminum busbar on the battery cell pole, and the through hole of the aluminum busbar corresponds to the position of the pole center point.

9. The automatic welding system for battery cell pole modules according to claim 7, characterized in that: Except for one side of the first slide rail, the other three sides of the base of the single-spot welding machine are provided with vertical walls. A group of Y-axis slide rails are provided on the opposite side walls. The Y-axis slide rail is bridged with the X-axis slide rail. The X-axis slide rail is provided with a fixed seat. The fixed seat is provided with a Z-axis slider. Tracks are provided on both sides of the Z-axis slider, and the Z-axis slider slides up and down through the tracks; an image acquisition module is provided on the side of the Z-axis slider, a laser transmitter head is provided at the bottom, and an aluminum row clamping mechanism is provided at the lower end of the laser transmitter head.

10. The automatic welding system for battery cell pole modules according to claim 7, characterized in that: The fixing fixture is provided with a square base plate with evenly distributed mounting holes, and fixing edges are provided on two adjacent sides of the base plate, which are fixed through the mounting holes; two clamping frames are also provided on the base plate, and clamping clamps are provided on the clamping frames; the clamping frames change the installation position through the mounting holes, and fix battery cell modules of different sizes through the clamping clamps.

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