Battery pack covering part installation springback prediction method and device and storage medium

Abstract

The invention relates to a battery pack covering part installation springback prediction method and device and a storage medium, and the method comprises the steps: building a battery pack covering part stamping process simulation model consistent with a battery pack covering part actual stamping forming process based on a battery pack covering part geometric model; the battery pack covering part stamping process simulation model is used for conducting full-process stamping simulation on a preset plate, and a simulation forming part meeting the preset formability evaluation requirement is obtained; according to an installation mode of a battery pack covering part and a battery pack box body in actual design, carrying out installation constraint on the simulation forming part; and on the basis of the geometric model of the battery pack covering part and the simulation forming part subjected to installation constraint, predicting the springback amount of the battery pack covering part after installation on the battery pack box body. According to the scheme, the springback value of the battery pack covering part after being installed on the battery pack box body can be predicted.

Description

Technical Field

[0001] The present invention relates to the technical field of power battery systems, and in particular to a method, device and storage medium for predicting the installation rebound of a battery pack cover. Background Art

[0002] When manufacturing battery pack covers, most of them adopt mature stamping forming processes. However, due to objective factors such as the large area of ​​battery pack covers, diverse designs, and high sheet stiffness, defects such as large springback often occur during the stamping process.

[0003] In order to quickly predict the springback amount of the battery pack cover, finite element software is usually used to simulate the formability and springback state of the battery pack cover, and the final springback amount is obtained by calculating the clamping springback results of the battery pack cover.

[0004] In 201610367405.8, a method for evaluating the rebound of automobile covers was provided, which can measure the rebound result after excluding gravity, but the measurement result is the free rebound result of the cover, which is inconsistent with the state that the bolt hole boundary of the cover is constrained after installation. Due to the large free surface and high material stiffness of the battery pack cover, the free rebound of the battery pack cover is large after the entire stamping process, and there is a large difference between the free rebound result and the rebound result after the final battery pack cover is installed.

[0005] Therefore, it is necessary to design a method that can predict the rebound amount of the battery pack cover after it is installed on the battery pack box. Summary of the invention

[0006] In order to predict the amount of rebound of a battery pack cover after it is installed on a battery pack box, the present application provides a battery pack cover installation rebound prediction method, device and storage medium.

[0007] The technical solution of this application is:

[0008] On the one hand, the present application provides a battery pack cover installation rebound prediction method, comprising:

[0009] Based on the geometric model of the battery pack cover, a battery pack cover stamping process simulation model consistent with the actual stamping forming process of the battery pack cover is constructed;

[0010] Use the battery pack cover stamping process simulation model to perform full-process stamping simulation on a preset plate to obtain a simulated molded part that meets preset formability evaluation requirements;

[0011] According to the installation method of the battery pack cover and the battery pack box in the actual design, the simulation molded part is installed with constraints;

[0012] Based on the geometric model of the battery pack cover and the simulated molded part after installation constraints, the rebound amount of the battery pack cover after installation on the battery pack case is predicted.

[0013] Preferably, according to the installation method of the battery pack cover and the battery pack box in the actual design, the step of installing the simulation molded part includes:

[0014] Establish a support model for the bolt connection surface of the battery pack box;

[0015] Taking the geometric model of the battery pack cover as a reference model, adding a locating pin model to the locating hole area of ​​the support model, and adding a bolt model to the bolt hole area of ​​the support model; the size of the locating pin model is consistent with the size of the locating pin of the battery pack cover in the actual design, and the size of the bolt model is consistent with the size of the mounting bolt of the battery pack cover in the actual design;

[0016] Adding locating pins to the locating hole area of ​​the simulation molded part in the free rebound state according to the locating pin model coordinates, and adding bolts to the bolt hole area of ​​the simulation molded part in the free rebound state according to the bolt model coordinates;

[0017] Adjusting the springback amounts in the X-direction and Y-direction of the bolt hole area of ​​the simulated molded part to 0 to constrain the displacement in the X-direction and Y-direction of the bolt hole area of ​​the simulated molded part;

[0018] The simulated nut tightening process adjusts the Z-direction springback amount of the nut tightening area to 0, so as to constrain the Z-direction displacement of the bolt hole area of ​​the simulated molded part.

[0019] Preferably, based on the geometric model of the battery pack cover and the simulated molded part after bolt constraint, the step of predicting the springback amount of the battery pack cover after installation on the battery pack box includes:

[0020] After constraining the bolt hole area of ​​the simulated molded part in displacement along the X-direction, the Y-direction and the Z-direction, calculating the Z-direction springback of the simulated molded part relative to the geometric model of the battery pack cover;

[0021] The Z-direction springback amount is determined as the springback amount of the battery pack cover after being installed on the battery pack box. Preferably, based on the battery pack cover geometric model, the step of constructing a battery pack cover stamping process simulation model consistent with the actual stamping forming process of the battery pack cover comprises:

[0022] According to the actual production line process of battery pack cover, plan the stamping simulation process flow of the whole process;

[0023] Perform hole patching, flange expansion and outer contour extension on the geometric model of the battery pack cover to obtain a hole patching geometric model, a flange expansion geometric model, an extended surface geometric model and a trimming curve;

[0024] Identify the features of the pre-designed battery pack cover geometric model to obtain the features of the battery pack cover; the features of the battery pack cover include: stamping features, trimming features, flanging features and punching features;

[0025] According to the hole filling geometric model, flange development geometric model, extended surface geometric model, trimming curve and battery pack cover features, the forming dies for each process consistent with the actual stamping process of the battery pack cover are constructed;

[0026] According to the actual stamping process requirements, corresponding simulation parameters are set for the forming dies of each process.

[0027] Preferably, the steps of constructing forming dies for each process consistent with the actual stamping forming process of the battery pack cover according to the hole filling geometric model, the flange development geometric model, the extended surface geometric model, the trimming curve and the battery pack cover features include:

[0028] Use the extended surface geometry model and stamping features to generate the drawing process die;

[0029] The flanging development geometry model, trimming curve and trimming features are used to generate the trimming process mold;

[0030] The hole filling geometry model and flanging features are used to generate the flanging process mold;

[0031] Use the punching feature to generate the punching process mold.

[0032] Preferably, according to the actual stamping process requirements, the step of setting corresponding simulation parameters for the forming die of each process includes:

[0033] Applying die scaling coefficients to the blank holder die, the concave die and the blank holder die in the drawing process die respectively;

[0034] Establish solid draw ribs for the blank holder die and die in the drawing process die;

[0035] Adjust the air cushion stroke of the blank holder die in the drawing process so that the air cushion stroke of the blank holder die is greater than the Z-direction height of the geometric model of the battery pack cover;

[0036] Add constant force to the blank holder die in the drawing process die;

[0037] Add a constant force to the pressing core mold in the trimming process mold, add a constant force to the pressing core mold in the flanging process mold, and add a constant force to the pressing core mold in the punching process mold.

[0038] Preferably, the parameters required to establish a solid draw bead include: the offset distance d1 of the draw bead from the contour line after the flange is unfolded, the draw bead section height h1, fillet r1 and fillet radius r2 of the holder ring mold, and the concave rib section fillet r3 and inner radius r4 of the die mold.

[0039] Preferably, the step of using the battery pack cover stamping process simulation model to perform full-process stamping simulation on a preset plate to obtain a simulated molded part that meets the preset formability evaluation requirements includes:

[0040] Evaluate the drawing formability of the simulated drawn parts after the drawing process;

[0041] After the drawing simulation molded part meets the preset drawing formability evaluation requirements, the drawing simulation molded part is subjected to trimming, flanging and punching processes to obtain the final simulation molded part;

[0042] The draw formability evaluation includes FLD evaluation, thinning rate evaluation, maximum comprehensive failure evaluation and wrinkling evaluation.

[0043] On the other hand, the present application also provides a battery pack cover installation rebound prediction device, comprising:

[0044] A simulation model building module, which is used to build a battery pack cover stamping process simulation model consistent with the actual stamping forming process of the battery pack cover based on the battery pack cover geometric model;

[0045] A simulation module, used to use the battery pack cover stamping process simulation model to perform full-process stamping simulation on a preset plate to obtain a simulated molded part that meets preset formability evaluation requirements;

[0046] A simulation molded part installation constraint module, used to constrain the installation of the simulation molded part according to the installation method of the battery pack cover and the battery pack box in the actual design;

[0047] The installation rebound amount prediction module is used to predict the rebound amount of the battery pack cover after installation on the battery pack body based on the geometric model of the battery pack cover and the simulated molded parts after installation constraints.

[0048] On the other hand, the present application also provides a storage medium having a computer program stored thereon. When the computer program is run on a computer, the computer is enabled to execute the battery pack cover installation rebound prediction method as described above.

[0049] The beneficial effects of the present invention are:

[0050] Since the battery pack cover is made of high-strength steel material, which has the problems of large springback and difficult mold compensation, the springback amount obtained by clamping detection with a gauge is quite different from the actual springback amount after installation. In the scheme of the present application, the actual designed geometric model of the battery pack cover and the actual stamping forming process of the battery pack cover are used to perform full-process stamping simulation on the preset sheet material, and installation constraints are added to the simulated molded parts to simulate the installation method of the battery pack cover and the battery pack case. The battery pack cover and the battery pack case are constrained by a bolt model to constrain the displacement of the bolt hole area, thereby achieving a true prediction of the springback amount of the battery pack cover after installation on the battery pack case. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 A schematic flow chart of the method for predicting the springback of a battery pack stamping cover installation provided in an embodiment of the present application. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0053] An embodiment of the present application provides a method for predicting the installation rebound of a stamped cover of a battery pack, which is applied to new energy vehicles.

[0054] like Figure 1 As shown, the method comprises the following steps:

[0055] S1. Obtain the geometric model and material parameters of the battery pack cover.

[0056] In an embodiment of the present application, a truly designed geometric model of the battery pack cover is imported into the sheet metal stamping CAE simulation software according to the conventional sheet metal forming analysis routine process.

[0057] In addition, by testing the performance of the battery pack cover material, the yield strength, tensile strength, sheet elongation, n value, r0, r45° value, and r90° value parameters of the battery pack cover are obtained, and the material model file of the battery pack cover is constructed.

[0058] S2. Perform finite element meshing on the geometric model of the battery pack cover and determine the stamping direction.

[0059] In an embodiment of the present application, the geometric model of the battery pack cover product is divided into finite element meshes and the stamping direction is adjusted according to the conventional process of traditional sheet metal forming analysis.

[0060] S3. Perform geometric processing on the geometric model of the battery pack cover to generate the model and curves required for the full process simulation.

[0061] In an embodiment of the present application, in order to obtain the model required for the full process flow simulation, the geometric model of the cover product can be filled with holes, flanging expanded and the outer contour extended, and the models required for the drawing process, trimming process, flanging process and punching process can be established in sequence.

[0062] Specifically, step S3 in the embodiment of the present application includes:

[0063] S31. Fill the bolt holes and positioning holes of the geometric model of the battery pack cover product to obtain a hole-filling geometric model.

[0064] In an embodiment of the present application, bolt holes and positioning holes with diameters within a specified diameter range in a geometric model of a battery pack cover product are identified, and the bolt holes and positioning holes within the specified diameter range are filled.

[0065] S32, unfolding the flange of the geometric model of the battery pack cover product to obtain a flange unfolded geometric model.

[0066] In an embodiment of the present application, the fillet areas and flange areas in the geometric model of the battery pack cover product are identified, and these fillet areas and flange areas are flanged 90 degrees.

[0067] S33. Extend the outer contour line of the geometric model of the battery pack cover product, create a product extension surface, and obtain an extended surface geometric model.

[0068] In an embodiment of the present application, the outer contour lines of the geometric model of the battery pack cover product are identified, and extended surfaces are created for the identified outer contour lines to obtain an extended surface geometric model.

[0069] The outer contour line can be the boundary line of the geometric model of the battery pack cover product, a section line, or other lines that define the shape of the product.

[0070] When creating an extension surface, you need to specify parameters such as the contour line, extension direction, and extension distance.

[0071] After the extension surface is created, adjust the curvature, direction, size and other parameters of the extension surface according to the actual situation to ensure that the shape of the extension surface is smoothly connected to the outer contour line.

[0072] S34, exporting the geometric model and curves created in steps S31 to S33.

[0073] In an embodiment of the present application, the geometric model of step S31 is extracted as the model required for the flanging process, the flanging unfolding geometric model of step S32 is extracted as the model required for the trimming process and the model required for the punching process, the outer contour line of the geometric model of the cover product in step S33 is extracted as the trimming curve, and the extended surface geometric model created for the outer contour line extension surface in step S33 is extracted as the model required for the drawing process.

[0074] S4. Plan simulation process plans and identify cover features based on actual production line processes.

[0075] The actual production line process includes: drawing process, trimming process, flanging process and punching process. In the embodiment of the present application, the actual drawing process, trimming process, flanging process and punching process are described. In the stamping forming CAE software, the read battery pack cover geometric model is feature detected to complete the identification of stamping features, trimming features, flanging features and punching features.

[0076] The simulation process scheme planned according to the actual production line process includes: adding a free springback simulation process after the drawing process; performing the positioning and gravity process before the trimming process, and adding a free springback simulation process after the trimming process; performing the positioning and gravity process before the flanging process, and adding a free springback simulation process after the flanging process; performing the positioning and gravity process before the punching process.

[0077] S5. Determine the stamping sheet size of the battery pack cover according to the outer contour dimensions of the stamping model and the trimming model to obtain a preset sheet.

[0078] In actual production, the size of the stamping sheet must accurately match the requirements of the stamping die and the trimming die to ensure that the battery pack cover that meets the design standards can be obtained after the stamping and trimming processes. In the stamping process, it is first necessary to produce a stamping model and a trimming model according to the design requirements of the battery pack cover product. The stamping model and the trimming model define the final shape and size of the battery pack cover product. Then, according to the outer contour dimensions of the stamping model and the trimming model, determine the size of the required stamping sheet, and trim or cut it; the trimmed or cut sheet is the preset sheet required for stamping, which is the basic material for stamping processing.

[0079] In an embodiment of the present application, a rectangular stamping sheet is established with reference to the outer contours of the stamping model and the trimming model of the battery pack cover product, and the contour line of the obtained rectangular stamping sheet is located inside the extended surface contour line of the extended surface geometric model obtained in S33.

[0080] S6. Establish production line molds based on the models and curves required for full process simulation.

[0081] In the embodiment of the present application, the model and curve required for the full process flow simulation generated in step S3 are called to complete the production line mold establishment, and Coulomb friction is applied to the production line. Specifically, step S6 includes:

[0082] S61, establishing the die for the drawing process, using the extended surface geometric model established in step S33 and the stamping features identified in step S4 to respectively generate the punch die, die die and blank holder die required in the drawing process.

[0083] In the embodiment of the present application, a free springback process is added after the drawing process is completed, and a die scaling coefficient is applied to the die of the drawing process. The die scaling coefficient calculation formula is:

[0084]

[0085] Among them, F S is the elastic scaling factor, σ b is the yield strength of the material, and E is the Young's modulus.

[0086] In the drawing process, due to the large flow and deformation of the material in the die, the friction between the die and the workpiece has a particularly significant impact on the forming quality. Therefore, adding a free springback process after the drawing process and applying a die scaling factor to the die is to compensate for the material springback and deformation caused by factors such as friction.

[0087] In an embodiment of the present application, the concave die mold required in the drawing process adopts the extension surface geometry model established in step S33, the punch mold required in the drawing process adopts the convex part of the extension surface geometry model established in step S33, and the pressure ring mold required in the drawing process adopts the extension surface geometry model with the convex part removed in step S33.

[0088] S62, the trimming process mold is established, and the flanging unfolding geometric model established in step S32, the trimming curve extracted in step S34, and the stamping features identified in step S4 are used to generate the core mold, the punch mold and the trimming mold in the trimming process respectively.

[0089] In an embodiment of the present application, positioning and gravity processes are performed before the trimming process begins, and a free rebound process is added after the trimming process ends. The trimming process pressing core and punch use step S32 to establish a flanging unfolding geometric model, and the trimming process trimming curve uses the trimming curve extracted in step S34.

[0090] S63, the flanging process mold is established, and the hole filling geometric model established in step S31 is used to generate the pressing core mold and the punch mold in the flanging process respectively, and the flanging feature identified in step S4 is used to generate the flanging mold.

[0091] In an embodiment of the present application, a positioning and gravity process is performed before the flanging process begins, and a free rebound process is added after the flanging process ends. The pressing core mold and the punch mold in the flanging process use the hole filling geometry model established in step S31, and the flanging process forming block uses the forming block model established after the flanging features are identified in step S4.

[0092] S64, punching process mold is established.

[0093] The punching features identified in step S4 are used to generate the core die, the punch die and the punching die in the punching process respectively.

[0094] In the embodiment of the present application, the positioning and gravity processes are performed before the punching process begins, and the pressing core, the punch and the punching die of the flanging process are generated after the punching features are identified in step S4.

[0095] S7, setting parameters for the production line mold obtained in S6.

[0096] In the embodiment of the present application, a solid draw rib is set in the drawing process to increase the drawing resistance of the plate, and a constant force is applied to the blank holder die in the drawing process, and a constant force is applied to the core die in the other processes. Specifically, step S7 includes:

[0097] S71, establishing solid draw ribs on the blank holder die and the die die established in step S61.

[0098] The parameters required to establish a solid drawbead include: the offset distance d1 between the drawbead and the contour line after the flange is unfolded, the drawbead section height h1, fillet r1 and fillet radius r2 of the blank holder die, and the concave rib section fillet r3 and inner radius r4 of the concave die. The above drawbead parameters can be determined by referring to the existing experience values ​​or design specifications in the industry. These experience values ​​or specifications are usually based on a large amount of practical experience and data analysis and have high reliability.

[0099] Among them, the offset distance d1 between the drawbead and the contour line after the flange is expanded is determined according to the specific shape and size of the stamping part and the material flow requirements. It should ensure that the drawbead can effectively control the flow direction and speed of the material to avoid defects such as wrinkling and rupture.

[0100] The drawbead cross-sectional height h1 determines the resistance of the drawbead to the material flow. The selection of its value should comprehensively consider factors such as the material's forming properties, stamping process requirements, and mold processing costs.

[0101] The design of the drawbead radius r1 and the fillet radius r2 should be conducive to reducing stress concentration and wear and improving the life of the die. The selection of these two values ​​is usually based on empirical values ​​and simulation analysis results.

[0102] The rib cross-section radius r3 and inner radius r4 of the die: These parameters should be designed to ensure that the rib can effectively contact the material and transmit pressure during the stamping process while avoiding excessive damage to the material.

[0103] S72, add a clamping force to the clamping ring mold of the drawing process established in step S61, add a constant force to the core mold of the trimming process established in step S62, add a constant force to the core mold of the flanging process established in step S63, and add a constant force to the core mold of the punching process established in step S64.

[0104] In the embodiment of the present application, the air cushion stroke h of the blank holder die in the drawing process is adjusted. q , so that the air cushion stroke h of the blank holder die in the drawing process q The Z-axis height of the battery pack cover product is 1mm to 5mm, and a constant force F is added to the blank holder die in the drawing process. y .

[0105] Add constant force F to the core die in the trimming process, flanging process and punching process x .

[0106] S8. Perform full-process stamping on the preset sheet material established in S5 according to the production line mold after the parameters are set in S7, and then perform formability analysis on the obtained battery pack cover simulation part.

[0107] In the embodiments of the present application, the product formability analysis mainly refers to the drawing formability evaluation of the sheet material, and the drawing formability evaluation includes FLD evaluation, thinning rate evaluation, maximum comprehensive failure evaluation and wrinkling evaluation.

[0108] By reading the simulation results of the battery pack cover geometry model, the advanced FLD diagram is displayed. The limit %FLC, acceptable thinning rate, critical safety %FLC, required thinning rate and acceptable thickening are changed according to the sheet material type to evaluate whether the product requirements are met.

[0109] The thinning rate assessment and the maximum comprehensive failure assessment are jointly assessed. If the thinning rate in a special area does not meet the requirements, the maximum comprehensive failure assessment value shall be referred to; it is required that there is no wrinkling during the forming process.

[0110] S9. Bolt installation springback prediction analysis.

[0111] In the embodiment of the present application, the springback prediction of the battery pack cover is performed by bolt installation. Specifically, step S9 includes:

[0112] S91. Establish a support model for the bolt connection surface of the battery pack body.

[0113] S92. Select a reference model, where the reference model is the geometric model of the battery pack cover in step S1.

[0114] S93. Add a locating pin model to the locating hole area of ​​the support model, and add a bolt model to the bolt hole area of ​​the support model; the size of the locating pin model is consistent with the locating pin size of the battery pack cover in the actual design, and the size of the bolt model is consistent with the installation bolt size of the battery pack cover in the actual design.

[0115] S94, adding locating pins to the locating hole area of ​​the simulated molded part in the free springback state according to the locating pin model coordinates, and adding bolts to the bolt hole area of ​​the simulated molded part in the free springback state according to the bolt model coordinates.

[0116] The simulated molded part in a free springback state refers to the simulated molded part in a free springback state after the final processing step.

[0117] S94, adjusting the springback amounts in the X-direction and Y-direction of the bolt hole region of the simulated molded part to 0, so as to constrain the displacement in the X-direction and Y-direction of the bolt hole region of the simulated molded part.

[0118] S95, the simulation nut tightening process adjusts the Z-direction springback amount of the nut tightening area to 0, so as to constrain the Z-direction displacement of the bolt hole area of ​​the simulation molded part.

[0119] S96. Output the predicted rebound value.

[0120] In the embodiment of the present application, the Z-direction rebound value of the battery pack cover relative to the reference model is output;

[0121] Evaluation index: Based on the Z-direction surface difference of the rebound area, the rebound performance of the battery pack cover after being installed on the battery pack body is predicted.

[0122] The embodiment of the present application also provides a battery pack cover installation rebound prediction device, comprising:

[0123] A simulation model building module, which is used to build a battery pack cover stamping process simulation model consistent with the actual stamping forming process of the battery pack cover based on the battery pack cover geometric model;

[0124] A simulation module, used to use the battery pack cover stamping process simulation model to perform full-process stamping simulation on a preset plate to obtain a simulated molded part that meets preset formability evaluation requirements;

[0125] A simulation molded part installation constraint module, used to constrain the installation of the simulation molded part according to the installation method of the battery pack cover and the battery pack box in the actual design;

[0126] The installation springback prediction module is used to predict the springback amount of the battery pack cover after installation on the battery pack box based on the geometric model of the battery pack cover and the simulated molded part after installation constraints. The embodiment of the present application also provides a storage medium on which a computer program is stored. When the computer program is run on a computer, the computer executes the battery pack cover installation springback prediction method as described above.

[0127] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0128] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0129] It should also be noted that, in this article, the orientation or position relationship indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the drawings, which is for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, relational terms such as "first" and "second" are used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations, nor can they be understood as indicating or implying relative importance. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements does not include those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such a process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0130] The technical solution provided by the present invention is described in detail above. The principle and implementation mode of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the present invention, and the content of this specification should not be understood as limiting the present invention. At the same time, for those skilled in the art, according to the present invention, there will be different forms of changes in the specific implementation mode and application scope. It is not necessary and impossible to list all the implementation modes here, and the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A method for predicting the springback of a battery pack cover during installation, characterized in that: include: Based on the geometric model of the battery pack cover, a battery pack cover stamping process simulation model consistent with the actual stamping forming process of the battery pack cover is constructed; Use the battery pack cover stamping process simulation model to perform full-process stamping simulation on a preset plate to obtain a simulated molded part that meets preset formability evaluation requirements; According to the installation method of the battery pack cover and the battery pack box in the actual design, the simulation molded part is installed with constraints; Based on the geometric model of the battery pack cover and the simulated molded part after installation constraints, the rebound amount of the battery pack cover after installation on the battery pack case is predicted.

2. The battery pack cover installation rebound prediction method according to claim 1, characterized in that: According to the installation method of the battery pack cover and the battery pack box in the actual design, the steps of installing the simulation molded part include: Establish a support model for the bolt connection surface of the battery pack box; Taking the geometric model of the battery pack cover as a reference model, adding a locating pin model to the locating hole area of ​​the support model, and adding a bolt model to the bolt hole area of ​​the support model; the size of the locating pin model is consistent with the size of the locating pin of the battery pack cover in the actual design, and the size of the bolt model is consistent with the size of the mounting bolt of the battery pack cover in the actual design; Adding locating pins to the locating hole area of ​​the simulation molded part in the free rebound state according to the locating pin model coordinates, and adding bolts to the bolt hole area of ​​the simulation molded part in the free rebound state according to the bolt model coordinates; Adjusting the springback amounts in the X-direction and Y-direction of the bolt hole area of ​​the simulated molded part to 0 to constrain the displacement in the X-direction and Y-direction of the bolt hole area of ​​the simulated molded part; The simulated nut tightening process adjusts the Z-direction springback amount of the nut tightening area to 0, so as to constrain the Z-direction displacement of the bolt hole area of ​​the simulated molded part.

3. The battery pack cover installation rebound prediction method according to claim 2, characterized in that: The step of predicting the springback amount of the battery pack cover after installation on the battery pack box body based on the geometric model of the battery pack cover and the simulated molded part after bolt constraint is performed includes: After constraining the bolt hole area of ​​the simulated molded part in displacement along the X-direction, the Y-direction and the Z-direction, calculating the Z-direction springback of the simulated molded part relative to the geometric model of the battery pack cover; The Z-direction rebound amount is determined as the rebound amount of the battery pack cover after being installed on the battery pack case.

4. The battery pack cover installation rebound prediction method according to claim 1, characterized in that: Based on the geometric model of the battery pack cover, the steps of constructing a battery pack cover stamping process simulation model consistent with the actual stamping forming process of the battery pack cover include: According to the actual production line process of battery pack cover, plan the stamping simulation process flow of the whole process; Perform hole patching, flange expansion and outer contour extension on the geometric model of the battery pack cover to obtain a hole patching geometric model, a flange expansion geometric model, an extended surface geometric model and a trimming curve; Identify the features of the pre-designed battery pack cover geometric model to obtain the features of the battery pack cover; the features of the battery pack cover include: stamping features, trimming features, flanging features and punching features; According to the hole filling geometric model, flange development geometric model, extended surface geometric model, trimming curve and battery pack cover features, the forming dies for each process consistent with the actual stamping process of the battery pack cover are constructed; According to the actual stamping process requirements, corresponding simulation parameters are set for the forming dies of each process.

5. The battery pack cover installation rebound prediction method according to claim 4, characterized in that: According to the hole filling geometric model, the flange development geometric model, the extended surface geometric model, the trimming curve and the battery pack cover features, the steps of constructing the forming molds for each process consistent with the actual stamping forming process of the battery pack cover include: Use the extended surface geometry model and stamping features to generate the drawing process die; The flanging development geometry model, trimming curve and trimming features are used to generate the trimming process mold; The hole filling geometry model and flanging features are used to generate the flanging process mold; Use the punching feature to generate the punching process mold.

6. The battery pack cover installation rebound prediction method according to claim 4, characterized in that: According to the actual stamping process requirements, the steps of setting the corresponding simulation parameters for the forming die of each process include: Applying die scaling coefficients to the blank holder die, the concave die and the blank holder die in the drawing process die respectively; Establish solid draw ribs for the blank holder die and die in the drawing process die; Adjust the air cushion stroke of the blank holder die in the drawing process so that the air cushion stroke of the blank holder die is greater than the Z-direction height of the geometric model of the battery pack cover; Add constant force to the blank holder die in the drawing process die; Add a constant force to the pressing core mold in the trimming process mold, add a constant force to the pressing core mold in the flanging process mold, and add a constant force to the pressing core mold in the punching process mold.

7. The battery pack cover installation rebound prediction method according to claim 6, characterized in that: The parameters required to establish a solid drawbead include: the offset distance d1 between the drawbead and the contour line after the flange is unfolded, the drawbead section height h1, fillet r1 and fillet radius r2 of the holder ring mold, and the concave rib section fillet r3 and inner radius r4 of the die mold.

8. The battery pack cover installation rebound prediction method according to claim 1, characterized in that: The steps of using the battery pack cover stamping process simulation model to perform full-process stamping simulation on a preset plate to obtain a simulated molded part that meets the preset formability evaluation requirements include: Evaluate the drawing formability of the simulated drawn parts after the drawing process; After the drawing simulation molded part meets the preset drawing formability evaluation requirements, the drawing simulation molded part is subjected to trimming, flanging and punching processes to obtain the final simulation molded part; The draw formability evaluation includes FLD evaluation, thinning rate evaluation, maximum comprehensive failure evaluation and wrinkling evaluation.

9. A battery pack cover installation rebound prediction device, characterized in that: include: A simulation model building module, which is used to build a battery pack cover stamping process simulation model consistent with the actual stamping forming process of the battery pack cover based on the battery pack cover geometric model; A simulation module, used to use the battery pack cover stamping process simulation model to perform full-process stamping simulation on a preset plate to obtain a simulated molded part that meets preset formability evaluation requirements; A simulation molded part installation constraint module, used to constrain the installation of the simulation molded part according to the installation method of the battery pack cover and the battery pack box in the actual design; The installation rebound amount prediction module is used to predict the rebound amount of the battery pack cover after installation on the battery pack body based on the geometric model of the battery pack cover and the simulated molded parts after installation constraints.

10. A storage medium having a computer program stored thereon, characterized in that: When the computer program is run on a computer, the computer is enabled to execute the battery pack cover installation rebound prediction method as described in any one of claims 1 to 8.

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