Battery welding system and battery welding method

Abstract

The application relates to a battery welding system and a battery welding method, the battery welding system comprising a welding head, a profiler and a servo motion module; wherein the profiler is used for acquiring a profile image of a step between the top cover and the shell, and obtaining a parameter measurement value of the step based on the profile image; the servo motion module is used for controlling the welding head to weld the top cover and the shell according to a preset welding track of the top cover and the shell and the parameter measurement value, and the profiler and the welding head are arranged on the servo motion module. By detecting the change of the step width in real time and adjusting the position of the welding focus relative to the relative fixation of the top cover boundary and the shell boundary, the welding of the top cover and the shell can be ensured to be based on the actual welding track at all times, and better welding quality is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery manufacturing, in particular to a battery welding system and a battery welding method. BACKGROUND

[0002] At present, when welding the top cover and the shell of a battery, the top cover welding machine adopts a key point position mode to confirm the welding track.

[0003] Taking a square battery as an example, as shown in Figure 1a , it is based on the assumption that the gap between the shell section of the top cover and the shell is a standard rectangle (the four vertices of the top cover and the shell are key points), and the ideal welding track is confirmed; as shown in Figure 1b , due to the influence of factors such as uneven gap between the shell and the top cover, shell deformation, and uneven pressure of the fixture clamp, the welding track is a wavy welding track.

[0004] In the welding process, due to the deformation of the welding track, it will cause uneven defocus amount, insufficient welding penetration consistency, welding through, bubbles, spatter and other welding defects during welding; how to adjust the welding track of the top cover welding machine in real time is a problem that needs to be solved to ensure welding. SUMMARY

[0005] The present application provides a battery welding system and a battery welding method to solve the problem of real-time adjustment of the welding head position during the welding of the top cover and the shell of a battery to ensure the welding quality. The technical solution of the present application is as follows:

[0006] According to the first aspect of the embodiment of the present application, a battery welding system is provided for welding the top cover and the shell of a battery, comprising: a welding head, a profilometer and a servo motion module; wherein the profilometer is used to obtain the profile image of the step between the top cover and the shell, and the parameter measurement value of the step is obtained based on the profile image; wherein the height and width between the top cover and the shell form the step after the cell of the battery enters the shell; the servo motion module, the profilometer and the welding head are arranged in the servo motion module, and are used to control the welding head to weld the top cover and the shell according to the preset welding track of the top cover and the shell and the parameter measurement value.

[0007] According to the second aspect of the embodiment of the present application, a battery welding method is provided for the above-mentioned battery welding system, the method comprising: obtaining the profile image of the step between the top cover and the shell; obtaining the parameter measurement value of the step based on the profile image of the step; the servo motion module moves according to the preset welding track and adjusts the welding head to be in the preset welding position based on the parameter measurement value of the step, so as to realize the welding of the top cover and the shell.

[0008] The technical solutions provided by the embodiments of the present application bring at least the following beneficial effects:

[0009] In the embodiments of the present application, by detecting the change of the step width in real time and adjusting the position of the welding focal point relative to the relative fixation of the top cover boundary and the shell boundary, the welding of the top cover and the shell can be ensured to be based on the actual welding track at all times, and better welding quality can be achieved.

[0010] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0011] The accompanying drawings incorporated in the specification and forming a part of it, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application, and are not intended to limit the application.

[0012] Figure 1a is a schematic diagram of an ideal welding track of a battery;

[0013] Figure 1b is a schematic diagram of an actual welding track of a battery;

[0014] Figure 2 is a schematic diagram of a battery structure provided by an embodiment of the present application;

[0015] Figure 3 is Figure 2 is a top view schematic diagram of a battery;

[0016] Figure 4 is a schematic diagram of a battery welding system provided by an embodiment of the present application;

[0017] Figure 5 is a schematic diagram of a battery welding result provided by an embodiment of the present application;

[0018] Figure 6 is a schematic diagram of a profile image detection process provided by an embodiment of the present application;

[0019] Figure 7 is a schematic diagram of a battery welding result provided by an embodiment of the present application;

[0020] Figure 8 is a schematic diagram of a step measurement parameter detection process provided by an embodiment of the present application;

[0021] Figure 9 is a schematic diagram of a welding quality detection process provided by an embodiment of the present application. DETAILED DESCRIPTION

[0022] In order for the ordinary person in the art to better understand the technical solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings.

[0023] It should be noted that the terms "first", "second" and the like in the description and claims of the present application and the above drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the present application as detailed in the appended claims.

[0024] It should be noted that the user information (including but not limited to user equipment information, user personal information, etc.) and data (including but not limited to data for display, analyzed data, etc.) involved in the present application are all information and data authorized by the user or authorized by all parties.

[0025] In the key point calibration based welding track between the battery top cover and the shell, the actual preset welding track is compared with the ideal preset welding track. Due to the influence of factors such as uneven gap between the shell and the top cover, shell deformation, and uneven pressure of the tool clamp, the welding track is deformed.

[0026] As shown in Figure 2 and Figure 3 , after the battery cell (not shown in the figure) enters the shell, the top cover and the shell have a height and a width between each other to form a step. Taking a square shell battery as an example, after the cell enters the shell, the top cover closes the port of the shell for the cell to enter the shell and covers the cell, the height of the top cover in the shell is lower than the height of the shell, which is the height of the step; the outer circumferential edge of the top cover has a certain width with the inner circumferential edge of the shell, which is the width of the step (also called gap, which is a reserved welding gap for forming a molten pool after welding). During the welding process of the battery top cover and the shell, the change of the step width needs to be detected in real time to ensure that the welding focal point is always located at the same preset welding position to weld the top cover and the shell. For example, the focal point of the welding is always located at the center position of the width. By detecting the change of the step width in real time and adjusting the position of the welding focal point relative to the fixed position of the top cover boundary and the shell boundary, the welding of the top cover and the shell can be ensured to be based on the actual welding track, and better welding quality can be achieved.

[0027] Based on this, the present application provides a battery welding system, as shown in Figure 4As shown, the welding system comprises a welding head 10, a profiler 20, a servo motion module 30, a welding feed motor 40, a gantry base 50, a gantry 60 and an industrial computer 70.

[0028] The welding head 10 and the profiler 20 are arranged on the servo motion module 30. The welding head 10 can be a laser welding head, which can keep the defocus amount stable during the movement and weld the top cover and the shell. The profiler 20 can be a 3D profiler, which can collect the step profile image of the top cover and the shell before welding and the molten pool image of the top cover and the shell after welding in real time during the movement. The servo motion module 30 can move along the axial direction and the transverse direction, which can drive the welding head 10 and the profiler 20 to move along the preset welding track between the top cover and the shell, and control the welding focal point of the welding head 10 to keep at the preset welding position based on the parameter measurement value during the movement.

[0029] In the battery welding system, the servo motion module 30 and the welding feed motor 40 are in a matching position. For example, when the welding feed motor 40 carrying the top cover and the shell of the battery is located below, the servo motion module 30 can be located above the welding feed motor 40. When the welding feed motor 40 carries the top cover and the shell to be welded to the preset position, the servo motion module 30 can move according to the preset welding track confirmed by a certain number of key points of the edge of the top cover and the edge of the shell (i.e. the cross-sectional shape of the top cover and the shell).

[0030] The servo motion module 30 is installed on the gantry base 50, and the gantry base 50 is installed on the gantry 60. In this way, the servo motion module 30, the profiler 20 and the welding head 10 are supported.

[0031] It should be further explained that the parameter measurement value of the step can be obtained based on the profile image, and the welding quality of the molten pool can be obtained based on the molten pool image.

[0032] Specifically, the profiler 20 comprises a transmitting assembly (not labeled in the figure) and a receiving assembly (not labeled in the figure). The transmitting assembly emits a transmitting light beam 21 to the top cover and the shell, and the receiving assembly receives a reflected light beam 22 of the transmitting light beam on the top cover and the shell, so that the profile image of the step is obtained, and the parameter measurement value of the step is obtained based on the profile image. In addition, the profiler is also used to obtain the molten pool image of the top cover and the shell after welding, so that the molten pool image of the molten pool is obtained, and the welding quality is obtained based on the molten pool image.

[0033] The industrial computer 70 is in communication connection with the welding head 10, the profilometer 20, the servo motion module 30 and the welding feed motor 40, for example, the communication connection is realized in the form of Ethernet. The industrial computer 70 calculates the parameter measurement value of the step based on the step profile image sent by the profilometer 20, and controls the servo motion module 30 to adjust the welding focal point of the welding head 10 to be located at the preset welding position in the process of moving according to the preset welding track, so as to control the welding head 10 to weld the top cover and the shell; synchronously, the profilometer 20 collects the real-time image of the completed molten pool, and the industrial computer 70 judges the welding quality based on the molten pool image sent by the profilometer 20. After each battery is welded, the industrial computer 70 controls the welding feed motor 40 to carry the top cover and the shell of the next battery to be welded to the preset position.

[0034] It needs to be further explained that the parameter measurement value of the step includes the center point coordinate of the step. In the process of moving according to the preset welding track, the industrial computer 70 adjusts the welding focal point of the welding head 10 to be located at the position of the center point coordinate of the step. Since the center point coordinate is detected in real time, when the welding gap between the top cover and the shell (i.e. the width of the step and / or the width changes) changes, the welding focal point of the welding head 10 can always be located at the coordinate position of the center point of the step when the change occurs, so as to ensure the stability of the defocus amount and the fit of the actual welding track and the actual step path.

[0035] In addition, the profilometer 20 is also used to collect the gray scale image of the completed welding molten pool in real time. The profilometer 20 can be arranged obliquely with the welding head 10, and the welding focal point axis of the welding head 10 and the emission beam of the profilometer 20 form an acute angle, so that the collection area of the profilometer 20 includes the longitudinal section of the step, so that the gray scale image of the molten pool collected by the profilometer 20 includes the image content of the molten pool in the step height direction. The profilometer 20 sends the gray scale image of the molten pool to the industrial computer 70, and the industrial computer 70 detects the welding quality of the molten pool based on the gray scale image of the molten pool.

[0036] Based on the above battery welding system, the embodiment of the present application also provides a battery welding method, as shown in the Figure 5 The method comprises the following steps:

[0037] Step 510: acquiring the profile image of the step between the top cover and the shell.

[0038] Step 520: obtaining the parameter measurement value of the step based on the profile image of the step. It can be known from Figure 3 that the parameter measurement value of the step includes the width (i.e. the welding gap), the height and the center point coordinate of the step.

[0039] Step 530: adjusting the preset welding position of the welding head based on the parameter measurement value of the step during the movement of the servo motion module according to the preset welding track, so as to realize the welding of the top cover and the shell.

[0040] As shown in Figure 6 and Figure 7 , the above step 510 includes:

[0041] Step 610: obtaining the point cloud image of the top cover and the point cloud image of the shell.

[0042] Step 620: reconstructing the point cloud image of the top cover and the point cloud image of the shell to obtain the contour image of the step.

[0043] Specifically, the light beams emitted by the emitting assembly are respectively irradiated on the top cover and the shell, the reflecting assembly receives the top cover point cloud image reflected by the top cover and the shell point cloud image reflected by the shell, and the top cover point cloud image and the shell point cloud image are reconstructed to obtain the top cover contour image, the shell contour image and the contour image of the step therebetween.

[0044] As shown in Figure 8 , the above step 520 includes:

[0045] Step 810: obtaining the width and height of the step based on the first reflected light beam, the second emitted light beam and the contour image of the step;

[0046] Step 820: obtaining the center point coordinates of the step based on the width and the height.

[0047] Specifically, as shown in Figure 7 , for example, in the case of embedding the top cover into the shell, at this time the top cover is low and the shell is high, the first emitted light beam and the second emitted light beam form a dislocation parallel line on the two planes corresponding to the top cover and the shell, and the width and the height of the step can be obtained based on the dislocation parallel line. Similarly, the horizontal center coordinates of the center point are obtained based on the center line point of the width, and the vertical center coordinates of the center point are obtained based on the center point of the height, thereby obtaining the center point coordinates of the step.

[0048] As shown in Figure 9 , the above step 530 includes:

[0049] Step 910: determining the preset welding position of the welding head based on the preset welding track and the center point coordinates during the movement of the servo motion module according to the preset welding track, wherein the preset welding track is obtained based on the edge of the top cover and the edge of the shell.

[0050] Step 920: Control the welding head to weld the top cover and the shell and form a molten pool in the step.

[0051] Cheng Figure 5 The battery welding system simultaneously monitors the welding quality in real time during the welding process. The method also includes the following steps:

[0052] Step 540: During the movement of the servo motion module according to the preset welding trajectory, acquire grayscale images of the molten pool of the top cover and the shell by the profilometer;

[0053] Step 550: Based on the grayscale image of the molten pool, confirm the welding quality of the step and the shell.

[0054] From the start to the end of welding, the profilometer 20 acquires images of the molten pool in real time during the welding process. The pre-trained defect detection neural network in the industrial control computer identifies the grayscale images of the molten pool, determines the welding quality, and records the welding quality assessment results of each frame into the database.

[0055] The current method for inspecting the welding quality of battery top cover and casing involves visual inspection after welding and sampling to measure the weld penetration depth. This method has the following drawbacks: (1) Visual inspection after welding only acquires images of the weld surface morphology and performs defect detection through image processing. It cannot observe the weld penetration depth and internal defects, and is easily affected by welding slag, welding dust, etc., leading to a high misjudgment rate; (2) The method of sampling the product after welding and cutting the weld to observe the penetration depth data of the end face to detect welding quality involves estimating the welding quality of a large batch of product welds with a small number of sample data, which is random and subjective. Based on the above method, the quality of the molten pool can be detected in real time, and its quality results can include the penetration depth and internal defects, achieving a better detection effect.

[0056] In an exemplary embodiment, a computer-readable storage medium is also provided, which, when the instructions in the storage medium are executed by the processor of the industrial control computer 70, enables an electronic device to perform the methods of the embodiments of this application.

[0057] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer readable storage medium. When the computer program is executed, the processes of the above-mentioned embodiments of the methods can be included. Any reference to memory, storage, databases, or other media in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration but not limitation, RAM is available in many forms such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0058] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the application being indicated by the following claims.

[0059] It should be understood that the application is not limited to the precise construction that has been described above and shown in the accompanying drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the application. The scope of the application is limited only by the appended claims.

Claims

1. A battery welding system for welding the top cover and casing of a battery, characterized in that, include: Welding joint; A profilometer is used to acquire a profilograph image of the step between the top cover and the housing, and to obtain parameter measurements of the step based on the profilograph image; wherein, after the battery cell is inserted into the housing, the height and width between the top cover and the housing form the step; A servo motion module is provided, in which the profilometer and the welding head are disposed. The servo motion module is used to move according to a preset welding trajectory and adjust the welding head to a preset welding position based on the parameter measurement values ​​of the step, thereby welding the top cover and the housing. The preset welding trajectory is obtained based on the edge of the top cover and the edge of the housing. The parameter measurement values ​​include the center point coordinates of the step. During the process of the servo motion module moving according to the preset welding trajectory, the welding focus of the welding head is adjusted to be located at the center point coordinates of the step. The profilometer is inclined to the welding head, and the welding focal axis of the welding head forms an acute angle with the emitted beam of the profilometer. The acquisition area of ​​the profilometer includes the longitudinal section of the step. The profilometer is also used to acquire a grayscale image of the molten pool in the step height direction after welding the top cover and the shell, so as to detect the welding quality of the molten pool. The battery welding system also includes an industrial control computer; the industrial control computer calculates the parameter measurement values ​​of the step based on the contour image of the step sent by the contour instrument, and controls the servo motion module to adjust the welding focus of the welding head to the preset welding position during the movement according to the preset welding trajectory, so as to control the welding head to weld the top cover and the shell.

2. The battery welding system according to claim 1, characterized in that, The profilometer includes a transmitting component and a receiving component. The transmitting component emits light beams to the top cover and the housing respectively, and the receiving component receives the reflected light beams from the top cover and the housing. The profilometer obtains the profile image based on the reflected light beams and obtains the preset welding position for welding the step based on the parameter measurement values ​​of the step.

3. The battery welding system according to claim 2, characterized in that, During the process of the servo motion module moving according to the preset welding trajectory, the profilometer collects grayscale images of the weld pool in real time and sends the grayscale images of the weld pool to the industrial control computer. The industrial control computer detects the welding quality of the weld pool based on the grayscale images of the weld pool.

4. A battery welding method for use in the battery welding system as described in any one of claims 1-3, the method comprising: Obtain a contour image of the step between the top cover and the housing; Based on the contour image of the steps, the parameter measurements of the steps are obtained; The servo motion module moves according to a preset welding trajectory and adjusts the welding head to a preset welding position based on the parameter measurement values ​​of the step, so as to achieve welding of the top cover and the shell; the preset welding trajectory is obtained based on the edge of the top cover and the edge of the shell; The parameter measurement values ​​include the center point coordinates of the step. During the process of the servo motion module moving according to the preset welding trajectory, the welding focus of the welding head is located at the center point coordinates of the step. The profilometer is inclined to the welding head, and the welding focal axis of the welding head forms an acute angle with the emitted beam of the profilometer. The acquisition area of ​​the profilometer includes the longitudinal section of the step. The profilometer also acquires a grayscale image of the molten pool in the step height direction after welding the top cover and the shell, which is used to detect the welding quality of the molten pool.

5. The battery welding method according to claim 4, characterized in that, The step of obtaining the contour image of the step between the top cover and the shell includes: Obtain point cloud images of the top cover and the shell; The point cloud images of the top cover and the shell are reconstructed to obtain the contour image of the steps.

6. The battery welding method according to claim 5, characterized in that, The method of obtaining parameter measurements of the steps based on the contour image of the steps includes: Based on the contour image of the steps, the width and height of the steps are obtained; Based on the width and height, the coordinates of the center point of the step are obtained.

7. The battery welding method according to claim 6, characterized in that, During the movement of the servo motion module according to the preset welding trajectory, the welding head is adjusted to a preset welding position based on the parameter measurement values ​​of the step, so as to achieve welding of the top cover and the shell, including: Based on the preset welding trajectory and the center point coordinates, the preset welding position of the welding head is determined during the movement of the servo motion module according to the preset welding trajectory. The welding head is controlled to weld the top cover and the shell, forming a molten pool within the step.

8. The battery welding method according to claim 7, characterized in that, The method further includes: During the movement of the servo motion module according to the preset welding trajectory, the grayscale image of the molten pool of the top cover and the shell is acquired by the profilometer. Based on the grayscale image of the molten pool, the welding quality of the step and the shell is confirmed.

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