Welding quality control method, welding method, and battery case

Abstract

The present application relates to a welding quality control method, a welding method and a battery shell. The welding quality control method comprises: obtaining a weld type; determining process parameters of each welding stage of the weld type based on the weld type; obtaining a first simulated welding result based on the weld type and the corresponding process parameters; confirming the process parameters of each welding stage if the first simulated welding result meets a first quality standard; determining welding process information based on the confirmed process parameters; obtaining a second simulated welding result based on the confirmed process parameters and the welding process information; and confirming the welding process information if the second simulated welding result meets a second quality standard. The present application reduces the welding deformation of metal products by integrating the test data of welding into finite element simulation simulation, performing finite element simulation calculation, and optimizing the welding process parameters and process information, thereby meeting the quality requirements, saving the production line post-production quality optimization cost and the amount of tooling fixture modification.

Description

Technical Field

[0001] This disclosure relates to the field of metal processing for vehicles, specifically to welding quality control methods, welding methods, and battery casings. Background Technology

[0002] Currently, with the rapid development of electric vehicles, major vehicle manufacturers have successively developed power battery packs to match them. Power battery systems, represented by lithium batteries, are the main power source for new energy vehicles, often referred to as their "heart." The power battery pack casing, as the carrier of battery cells / modules, plays a crucial role in the safety protection of new energy batteries. During manufacturing, in addition to meeting the strength and rigidity requirements under load-bearing conditions, it also needs to meet high manufacturing precision to accommodate the installation conditions of the cells / modules. To achieve the goal of lightweight battery packs, aluminum alloy materials are mostly used for the battery pack casing, with arc welding as the main welding and connection process. However, due to the low rigidity of aluminum alloy and the large number of weld seams in the battery casing, the welding process of aluminum alloy casings is prone to significant welding deformation, affecting welding quality and assembly precision. Currently, the industry's methods for controlling welding deformation still rely heavily on extensive experimental exploration of welding and anti-deformation fixture control, lacking rapid and effective standard control methods. Given the large number of weld seams in metal products, current welding methods result in significant welding deformation of the battery casing after welding, making it difficult to guarantee manufacturing precision. Summary of the Invention

[0003] To overcome the problems existing in the related technologies, this disclosure provides, by way of example, a welding quality control method, a welding method, and a battery casing.

[0004] An exemplary embodiment of the first aspect of this disclosure provides a welding quality control method, comprising: acquiring a weld type; determining process parameters for each welding stage of the weld type based on the weld type; obtaining a first simulated welding result based on the weld type and the corresponding process parameters; determining whether the first simulated welding result meets a first quality standard; if the first simulated welding result meets the first quality standard, confirming the process parameters for each welding stage; if the first simulated welding result does not meet the first quality standard, re-determining the process parameters for each welding stage of the weld type; determining welding process information based on the confirmed process parameters; obtaining a second simulated welding result based on the confirmed process parameters and the welding process information; determining whether the second simulated welding result meets a second quality standard; if the second simulated welding result meets the second quality standard, confirming the welding process information; if the second simulated welding result does not meet the second quality standard, re-determining the welding process information.

[0005] In some embodiments, obtaining the first simulated welding result based on the weld type and the corresponding process parameters includes: obtaining the first simulated welding result based on the weld type and the corresponding process parameters through a first finite element simulation model, wherein the finite element simulation model is a double ellipsoidal heat source model established based on the heat source power parameters of various weld types obtained experimentally.

[0006] In some embodiments, obtaining a second simulated welding result based on the confirmed process parameters and the welding process information includes: obtaining the second simulated welding result through a second finite element simulation model based on the confirmed process parameters and the welding process information, wherein the second finite element simulation model is a deformation prediction model.

[0007] In some embodiments, the first quality standard includes one or more of the following: joint shape, joint strength, and joint stiffness.

[0008] In some embodiments, the second quality standard includes: deformation amount.

[0009] In some embodiments, the welding stage includes: an arc initiation stage, a stabilization stage, and an arc termination stage.

[0010] In some embodiments, the process parameters include: welding speed, welding voltage, and welding current.

[0011] In some embodiments, the welding process information includes one or more of the following: welding sequence, fixture type, and fixture position.

[0012] Secondly, according to some other exemplary embodiments, this disclosure also provides a welding method for metal products, wherein the welding method includes: confirming process parameters and welding process information by means of the welding quality control method described in the first aspect; and welding the metal product based on the confirmed process parameters and the confirmed welding process information.

[0013] Thirdly, according to some other exemplary embodiments, this disclosure also provides a battery housing, wherein the battery housing includes a metal frame manufactured by the welding method described in the second aspect.

[0014] The technical solutions provided by the embodiments of this disclosure can include the following beneficial effects: by incorporating welding test data into finite element simulation, and through finite element simulation calculations, welding process parameters and flow information are optimized collaboratively to minimize welding deformation of metal products and meet quality requirements. This simulation can save on-site quality optimization costs and tooling / fixture modifications in the later stages of the production line.

[0015] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0016] This disclosure can be better understood by describing exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, in which:

[0017] Figure 1 This is a schematic diagram of a welding quality control method flow according to an exemplary embodiment of a disclosed document;

[0018] Figure 2 This is a schematic diagram of the heat source power parameters for three stages of weld welding, as shown in an exemplary embodiment of a disclosed document;

[0019] Figure 3 This is a schematic diagram of the clamping arrangement of a tooling fixture for controlling welding deformation of a battery casing, as shown in another exemplary embodiment disclosed.

[0020] Figure 4 This is a schematic diagram of the welding sequence of the battery casing according to another exemplary embodiment disclosed;

[0021] Figure 5 This is a schematic diagram illustrating the welding sequence of the battery casing and the clamping arrangement of the tooling fixtures according to an exemplary embodiment disclosed in a book.

[0022] Figure 6 This is a schematic diagram illustrating the welding deformation result of a battery casing according to an exemplary embodiment disclosed in a publication. Detailed Implementation

[0023] The following describes specific embodiments of this disclosure. It should be noted that, in order to provide a concise description, this specification cannot exhaustively describe all features of the actual embodiments. It should be understood that, in the actual implementation of any embodiment, just as in any engineering or design project, various specific decisions are often made to achieve the developer's specific goals and to meet system-related or business-related constraints, and this can change from one embodiment to another. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this disclosure, changes in design, manufacturing, or production based on the technical content disclosed in this disclosure are merely conventional technical means and should not be construed as insufficient content of this disclosure.

[0024] Unless otherwise defined, the technical or scientific terms used in the claims and description shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this patent application description and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. The terms “an” or “a” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising” or “including” and similar terms mean that the element or object preceding “comprising” or “including” encompasses the element or object listed following “comprising” or “including” and its equivalents, and do not exclude other elements or objects. The terms “connected” or “linked” and similar terms are not limited to physical or mechanical connections, nor are they limited to direct or indirect connections.

[0025] In some related technologies, the battery casings of plug-in hybrid electric vehicles or small-capacity pure electric vehicles are made of steel or aluminum castings, avoiding the issue of welding deformation. However, with the rapid increase in the capacity of pure electric vehicle power batteries, the size of battery casings has gradually increased to 1.8m in length and 1.5m in width. Material costs and process technology no longer support casting as a process route for battery casings. In other related technologies, to control welding deformation of the battery casing, extensive welding experiments and large anti-deformation control fixtures are used as implementation paths. This approach requires significant material and time costs. Even if welding deformation is ultimately controlled within the acceptable range of quality standards, battery casings produced using these methods often have a large amount of residual stress inside, making them highly susceptible to weld cracking under fatigue application conditions. Therefore, the quality stability of the manufacturing process is highly volatile. In some related technologies, to reduce welding deformation of the battery casing, aluminum spot welding is used in some areas instead of arc welding during battery casing process development, leading to a significant increase in material costs. Furthermore, because the main frame of the battery casing is made of aluminum profiles or castings, arc welding cannot be avoided.

[0026] To solve the aforementioned technical problems, such as Figure 1 As shown, this disclosure provides a welding quality control method, which may include steps S110-S170, as detailed below.

[0027] Step S110: Obtain the weld type. The joint type for each welding location can be determined, such as a standard butt joint, a butt joint with a single-sided V-groove, a corner joint, and a T-joint. Based on the joint type for each welding location, the weld type is determined, such as: horizontal weld, zigzag weld, vertical weld, T-joint weld, and corner weld.

[0028] Step S120: Based on the weld type, determine the process parameters for each welding stage of the weld type. According to the weld type, the process parameters for each weld can be initially set and then verified through simulation.

[0029] In some embodiments, process parameters may include welding speed, welding voltage, and welding current. Welding speed and power directly affect the shape and strength of the weld joint. This disclosure embodiment can confirm the process parameters for each weld seam through simulation, ensuring that the welding of each seam meets quality requirements, thereby improving the overall welding quality.

[0030] In some embodiments, the welding stage may include: an arc initiation stage, a stabilization stage, and an arc termination stage. For example... Figure 2 As shown, the welding power varies at different stages. In this embodiment, the welding is divided into three stages to confirm the process parameters, which can be accurately judged by the model and can also refine the welding process and improve the welding quality.

[0031] Step S130: Based on the weld type and corresponding process parameters, obtain the first simulated welding result. Simulation results are obtained according to the type of each weld and the set process parameters for each weld.

[0032] In some embodiments, step S130, obtaining a first simulated welding result based on the weld type and corresponding process parameters, may include: obtaining the first simulated welding result using a first finite element simulation model based on the weld type and corresponding process parameters, wherein the finite element simulation model is a double ellipsoidal heat source model established based on heat source power parameters of various weld types obtained experimentally. In this embodiment, a finite element simulation model can be established, and the input process parameters can be simulated using the finite element simulation model to obtain the first simulated welding result. Based on this, it can be determined whether the input process parameters can meet the quality requirements, thereby confirming the process parameters or making further adjustments. In this embodiment, the finite element simulation model can be established based on experimental data, thereby ensuring the accuracy and reliability of the simulation. Based on the welding quality requirements of each joint, a preliminary tooling and fixture scheme was developed. Combining metallographic experimental data obtained from sample welding tests, a table of heat source power parameters for the three welding stages (arc initiation, welding, and arc termination) for each typical weld was determined. Finite element simulation models of different types of arc welded joints were established. Tetrahedral meshing and a double ellipsoidal heat source model were used to analyze the influence of joint type, tooling and fixture, and heat source power parameters on joint quality. In the model, a segmented double ellipsoidal heat source was selected. Under the premise of ensuring that the total input heat and loading time remain constant, the uniform heat generation rate in the weld element was used to represent the welding heat input process. In the actual welding process, in addition to the stable welding stage, there is a 0.4s ignition and arc initiation stage at the beginning of welding, and a 1.3s low-power arc termination stage after welding to improve crater formation. The power of these three stages needs to be considered separately. The power of each stage is converted into a unit volume heat generation rate and applied to the weld element, constructing a parameter library of unit volume heat generation rates for each joint of the lower shell frame.

[0033] Step S140: Determine whether the first simulated welding result meets the first quality standard. If the first simulated welding result meets the first quality standard, confirm the process parameters for each welding stage. If the first simulated welding result does not meet the first quality standard, return to step S120 to redetermine the process parameters for each welding stage of the weld type. Determine whether the set process parameters meet the standard; if not, readjust the process parameters and resimulate; if they do, confirm the process parameters. Simulation can efficiently confirm the feasibility of the welding scheme and whether the quality meets the requirements.

[0034] In some embodiments, the first quality standard may include one or more of the following: joint shape, joint strength, and joint stiffness. The standard can be determined by whether the simulated welded joint shape meets the requirements; it can also be confirmed whether the quality standard is met based on the simulated joint strength, stiffness, and other information. By making judgments from multiple angles and aspects, it is possible to more accurately confirm whether the process standards meet the requirements, thereby ensuring the reliability of the simulation and improving the quality of actual welding.

[0035] Step S150: Based on the confirmed process parameters, determine the welding process information. The welding process information can be further determined based on the confirmed process parameters. By simulating, confirming, and adjusting separately, it is possible to avoid introducing too many variable parameters at once, which would lead to model complexity, and also to avoid interference between multiple parameters, preventing efficient adjustment.

[0036] In some embodiments, welding process information may include one or more of the following: welding sequence, fixture type, and fixture location. The welding sequence for each weld can be designed by combining process parameters for different joint types. Based on the welding sequence, tooling fixtures for joints at different locations can be determined, and a preliminary welding sequence, welding process parameters, and tooling fixture arrangement scheme for the battery casing frame can be formulated. Different welding sequences at multiple welding locations will result in different stress conditions, leading to different deformations. The type of fixture may include pins (such as...). Figure 3 The embodiments disclosed herein can not only adjust and simulate parameters such as welding time and power, but also confirm the sequence of multiple welding positions, the type of fixture, and the clamping position of the fixture, thereby comprehensively simulating and controlling the welding process and improving the reliability of product manufacturing, especially improving the quality of multi-welded metal products such as battery casing frames.

[0037] Step S160: Based on the confirmed process parameters and welding process information, a second simulated welding result is obtained. After confirming the process parameters, the set welding process information can be confirmed. Through simulation, the welding results under different welding processes can be judged, thereby efficiently confirming whether the welding process is feasible and whether it meets comprehensive quality requirements.

[0038] In some embodiments, a second simulated welding result is obtained based on confirmed process parameters and welding process information, including: obtaining the second simulated welding result through a second finite element simulation model based on confirmed process parameters and welding process information, wherein the second finite element simulation model is a deformation prediction model. Embodiments of this disclosure can establish a finite element simulation model of a multi-weld arc welding process, obtain the deformation law during the welding process, and by defining trend curves of the welded product along three perpendicular coordinate directions with time or displacement in the finite element program, it is possible to quickly determine whether the welding deformation meets the quality requirements.

[0039] Step S170: Determine whether the second simulated welding result meets the second quality standard. If the second simulated welding result meets the second quality standard, confirm the welding process information. If the second simulated welding result does not meet the second quality standard, return to step S150 to re-determine the welding process information. By using simulation to determine whether the quality standard is met, the feasibility of the set welding process information can be efficiently confirmed, and infeasible solutions can be adjusted in a timely manner and confirmed again through simulation.

[0040] In some embodiments, the second quality standard may include: deformation amount. In welding processes, deformation amount is an important indicator for measuring welding quality. By determining the feasibility of process flow information through deformation amount, the simulation results of the welding process are made more reliable.

[0041] In some embodiments, the welding quality control method may include conducting welding experiments based on the finally confirmed welding process parameters and welding flow information to verify whether the actual deformation amount meets the deformation amount standard. This allows for more reliable confirmation that the parameter information meets the quality requirements.

[0042] The welding quality control method of this disclosure optimizes the heat source power parameters of each weld seam in the three stages of welding (arc initiation, welding, and arc termination) through finite element simulation, constructs a parameter library of heat generation rate per unit volume for various joints, reduces the welding deformation of a single weld seam while meeting the weld seam strength requirements, and obtains welded products with small deformation and high precision by optimizing the welding sequence of multiple weld seams and the layout of the clamping points of the corresponding welding fixtures.

[0043] Based on the same inventive concept, this disclosure also provides a welding method for metal products, comprising: confirming process parameters and welding process information using the welding quality control method as described in any of the foregoing embodiments; and welding the metal product based on the confirmed process parameters and welding process information. The welding quality control method can efficiently confirm process parameters and welding process information, and the information is highly reliable, thus ensuring the quality of the welded metal product.

[0044] Based on the same inventive concept, this disclosure also provides a battery casing, wherein the battery casing includes a metal frame, the metal frame being manufactured by the welding method as described in any of the foregoing embodiments. The aforementioned welding method ensures the quality of the battery casing.

[0045] In some embodiments, the battery housing frame structure may be configured as, but is not limited to, a battery housing with modules placed in a box or a battery housing with cells placed directly in a box.

[0046] In some embodiments, the frame of the battery casing may be made of aluminum alloy, and the battery casing frame structure may be configured to be made of materials including but not limited to 6-series aluminum alloy, 7-series aluminum alloy, etc., and the manufacturing process may be configured to include but not limited to extrusion, casting, stamping, etc.

[0047] The method for the battery casing provided in this disclosure is illustrated with a specific example. For instance... Figure 3 As shown, the battery casing frame structure may include a left side frame 11, a front side frame 12, a right side frame 13, a bottom side frame 14, longitudinal beams 15, 12 crossbeam structures 16, and a tooling fixture clamping structure 17. The battery casing material may be 6-series aluminum alloy, and the welding process may be arc welding. The steps for controlling welding deformation of the aluminum alloy battery casing can be as follows:

[0048] Step 1: Based on the structural characteristics of the aluminum alloy battery casing frame, the types of welding joints are proposed as follows: butt welds (including horizontal welds, zigzag welds, and vertical welds), T-joint welds, and fillet welds.

[0049] Step 2: Develop a preliminary tooling and fixture scheme. Based on the metallographic experimental data obtained from the sample welding test, determine the heat source power parameter table for the three stages of welding (arc initiation, welding, and arc termination) for each typical weld. Construct a parameter library of unit volume heat generation rate for four types of joints in the lower shell frame. Use tetrahedral meshing and double ellipsoidal heat source model to establish finite element simulation models for different types of aluminum alloy arc welding joints.

[0050] Step 3: Combine metallographic experiments to evaluate whether the aluminum alloy arc welded joint under the above welding process parameters and tooling fixture scheme meets the quality requirements such as joint strength; if not, repeat steps 2-3, adjust the heat source power parameters and tooling fixture clamping scheme to obtain process parameters that meet the welding quality requirements.

[0051] Step 4: Determine the welding sequence for the multiple welds on the aluminum alloy battery casing frame. This can be done as follows: Figure 4 As shown, S1-S6 represent welding steps 1-6 respectively;

[0052] Step 5: Design the tooling and fixture clamping layout for the welding process according to the welding sequence, including pins, support clamps, single clamps, and single supports;

[0053] Step 6: Integrate the welding sequence and the corresponding tooling and fixture clamping layout diagram, as shown below. Figure 5 As shown;

[0054] Step 7: Establish a simulation model for predicting welding deformation of the aluminum alloy battery casing frame. The calculation results are as follows: Figure 6 As shown, the maximum deformation meets the manufacturing quality requirements of the battery pack.

[0055] This application uses specific terms to describe embodiments of the application. Terms such as "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of the application. Therefore, it should be emphasized and noted that references to "an embodiment," "one embodiment," or "an alternative embodiment" in different locations throughout this specification do not necessarily refer to the same embodiment. Furthermore, certain features, structures, or characteristics in one or more embodiments of the application can be appropriately combined.

[0056] In the context of this application, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of explicitly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0057] Similarly, it should be noted that, in order to simplify the description of the present application and thus aid in the understanding of one or more embodiments, the foregoing description of the embodiments of the present application sometimes combines multiple features into a single embodiment, drawing, or description thereof. However, this disclosure method does not imply that the subject matter of the present application requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of the single embodiments disclosed above.

[0058] The basic concepts have been described above. Obviously, for those skilled in the art, the above disclosure is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore remain within the spirit and scope of the embodiments of this application.

Claims

1. A welding quality control method, comprising: Get the weld type; Based on the weld type, determine the process parameters for each welding stage of the weld type; Based on the weld type and the corresponding process parameters, the first simulated welding result is obtained; Determine whether the first simulated welding result meets the first quality standard, wherein the first quality standard includes one or more of the following: joint shape, joint strength, and joint stiffness; If the first simulated welding result meets the first quality standard, then the process parameters for each welding stage are confirmed. If the first simulated welding result does not meet the first quality standard, the process parameters for each welding stage of the weld type are re-determined. Based on the confirmed process parameters, determine the welding process information; Based on the confirmed process parameters and the welding process information, a second simulated welding result is obtained; Determine whether the second simulated welding result meets the second quality standard, wherein the second quality standard includes: deformation amount; If the second simulated welding result meets the second quality standard, then the welding process information is confirmed; If the second simulated welding result does not meet the second quality standard, the welding process information is redefined.

2. The welding quality control method according to claim 1, wherein, The first simulated welding result is obtained based on the weld type and the corresponding process parameters, including: Based on the weld type and corresponding process parameters, the first simulated welding result is obtained through the first finite element simulation model, wherein the finite element simulation model is a double ellipsoidal heat source model established based on the heat source power parameters of various weld types obtained from experiments.

3. The welding quality control method according to claim 1, wherein, Based on the confirmed process parameters and the welding process information, a second simulated welding result is obtained, including: Based on the confirmed process parameters and the welding process information, the second simulated welding result is obtained through the second finite element simulation model, wherein the second finite element simulation model is a deformation prediction model.

4. The welding quality control method according to claim 1, wherein, The welding stages include: arc initiation stage, stabilization stage, and arc termination stage.

5. The welding quality control method according to claim 4, wherein, The process parameters include: welding speed, welding voltage, and welding current.

6. The welding quality control method according to claim 1, wherein, The welding process information includes one or more of the following: welding sequence, fixture type, and fixture position.

7. A welding method for metal products, wherein, The welding method includes: The process parameters and welding process information are confirmed by the welding quality control method as described in any one of claims 1-6; Based on the confirmed process parameters and the confirmed welding process information, the metal product is welded.

8. A battery casing, wherein, The battery casing includes a metal frame, which is manufactured by the welding method as described in claim 7.

Images