Due to the poor wettability and thermal stability of electrolyte, the application of traditional lithium ion battery separator in the field of high-performance and high safety battery is limited. The surface modification of the separator to realize its surface functionalization has become a feasible strategy to solve the inherent problems of lithium-ion battery separators. From perspective of surface physical modification and surface chemical modification, this paper elaborated respectively the features and cutting-edge dynamics of various surface modification methods, such as spray coating, dip coating, solution casting, electrospinning, chemical grafting, plasma, radiation grafting and UV grafting. The paper also indicated that developing multifunctional separators, intelligent response separators, and reducing modification costs would be the research directions for surface modification of lithium-ion battery separators in the future.

The current cleaning solvent has the problem of endless cleaning for the long used automobile base coat pipeline. In this paper, the principle of paint remover was applied to the cleaning of automobile paint pipelines. A cleaning solvent and its corresponding cleaning program with benzyl alcohol and lye as the main agents and ethylene glycol butyl ether, isopropyl alcohol and ethyl acetate as auxiliary agents were developed to realize efficient cleaning of paint transfer pipelines. The results show that, compared with traditional cleaning solvents, this formula is not only suitable for water-based paint topcoat systems, but also for solvent-based topcoat systems, and the cleaning effect of long-term used pipes is greatly improved, the cleaning time is shortened by more than 50%, the cost of cleaning materials and VOC emissions are reduced by 50%, and the cleaning efficiency of the paint transfer system is effectively improved.

To meet the development needs of commercial vehicle light weight, from the perspective of materials light weight, the original glass fiber composite deflectors were replaced by Carbon Fiber Reinforced Plastics (CFRP) deflectors, It is achieved that the weight is reduced by 30% and the performance index is consistent, and even better. Based on the composite material failure criterion of 3D-Hashin and Cohesive layered failure criterion, a simulation model of basic mechanical properties of CFRP was established, and the effectiveness of the model was verified by comparing with experimental results. through the design of CFRP layer angle, finite element modeling was founded, the modal performance and stiffness of the 2 materials deflectors were compared and analyzed, the results show that the theoretical quality of carbon fiber reinforced plastics (CFRP) deflectors model is reduced, at the same time, compared with the original glass fiber composites deflectors, the modal performance and the average stiffness increase, and meet the fracture strength requirements.

The dissimilar galvanized steel sheets with thickness of 0.7 mm St17E and FC180/340HD for car door were tested and studied for laser welding process. The effects of key process parameters (laser power and welding speed) on the weld surface morphology and weld cross section were investigated. The microstructure and mechanical properties of welded joints were analyzed and evaluated. The results indicate that when the laser power and welding speed are 1 300 W and 2.0 m/min respectively, there are less welding spatters and the weld surface is smooth. As the laser power increases and the welding speed decreases, the weld penetration depth and weld area increase. For the dissimilar galvanized steel sheets welded joint, the hardness of the St17E base metal is the lowest, and the hardness of the weld zone is much higher than that of the base metal zone. The tensile specimen of the welded joint obtained with optimized parameters fractures in the St17E base metal.

In order to eliminate surface defects around the roof antenna mounting boss, this paper used Autoform simulation and experimental verification to analyze 2 causes of defects, cause 1: stroke during the forming process is small, and the plastic deformation of the material is insufficient; cause 2: the pressing force of the pressing plate is insufficient, resulting in the deformation in the deformation area affecting the non-deformed area. Through the simulation analysis of the 2 process methods of the antenna mounting boss drawing forming and upper forming, it is confirmed that the upper forming process can effectively solve the defect around the antenna mounting boss, and the real effect is completely consistent with the theoretical simulation, which solves the problem of the surface defect of the antenna boss.

A complete visual inspection system based on YOLOv5 combining with PLC, RFID, Python, OpenCV and DingTalk, was designed to replace manual inspection and recognition of the installation status of automotive parts. Accuracy and recall rate of the sample models trained in this system are both above 98%. From actual operation observation, the probability of identifying and accurately reminding is above 99%, and it meets the requirements of production takt, superior to the actual results of current manual detection, with low cost and good economic promotion.

Bolt connection is the most commonly used connection technology in automobile industry, its connection failure is a common problem in automobiles, in particular, bolt looseness is the most common problem. Through the research on self-tapping locking bolt, it is found that it has the advantages of high connection reliability, repeated use and low system cost. Through the bolt assembly process development, the difference of torque-clamping force relationship with ordinary bolts was distinguished, the assembly process parameters were determined and reliable bolt connection was realized.

This paper elaborated the application trend of mechanical connection technology in automotive Body In White (BIW) manufacturing. Semi-hollow and self-piercing riveting technology as the most widely applied technology of steel aluminum connecting, its process technology parameters are crucial to BIW connection strength. This paper elaborated the semi-hollow and self-piercing riveting process and quality control method as well as 2 common quality defects of semi-hollow self-piercing rivet of BIW in mass production of automobile, analyzed the influencing factors of lack of height and rupture of closed end of rivet. By commissioning of riveting equipment and optimization of riveting process parameters, the above defects were solved, providing solution and direction to solve quality issues in BIW manufacturing.

This article studied the background values of DNPH tubes, with focus on exploring the effects of different brands of DNPH tubes on the recovery rates of formaldehyde, acetaldehyde and acrolein, as well as the impacts of the same brand of DNPH tubes on the recovery rates of different aldehydes, as well as the impacts of sampling conditions on the recovery rates of aldehydes. It was found that different brands have smaller impacts on the recovery rates of formaldehyde and acetaldehyde, but greater impacts on the recovery rates of acrolein. Similarly, different sampling conditions have little impact on the recovery rates of formaldehyde and acetaldehyde, but have significant impacts on the recovery rates of acrolein.

To solve the problems existing in the selection method of typical test conditions of the traditional load spectrum, this paper explored the potential relationship between process parameters by fuzzy clustering analysis, and realized the classification and primary selection of operating conditions data, meanwhile, the fuzziness of the classification process was fully considered and the subjective randomness of the preliminary selection of the scheme was avoided. On the basis of the preliminary selection results, the Analytic Hierarchy Process (AHP) was introduced to comprehensively consider the 4 comprehensive evaluation indexes, namely, the typicality and comprehensiveness of the selection of test conditions, the economy of the test and the amount of spectral data. The hierarchical structure model of the system was established, and the representative test conditions were selected by combining qualitative analysis and quantitative calculation, thus improving the scientificity and systematization of the selection of typical test conditions.