In order to improve quality and performance of battery material, and address the battery safety issue, the contents of nickel, cobalt and manganese elements in the cathode materials of ternary lithium batteries are accurately determined by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES), and the uncertainty in the measurement process is systematically evaluated according to the standard of JJF 1059.1—2012 “Evaluation and Representation of Measurement Uncertainty”. The uncertainty factors that may be introduced in each part of the test are deeply analyzed, and these uncertainties are carefully quantified and calculated. When the nickel content of the sample is 5.521 μg/mL, the extended uncertainty is U₉₅(Ni)=0.013 1 mg/kg. When the content of cobalt is 3.566 μg/mL, the extended uncertainty is U₉₅(Co)=0.011 8 mg/kg; when the manganese content is 2.102 μg/mL, the extended uncertainty is U₉₅(Mn)=0.013 1 mg/kg. Finally, the synthetic uncertainty of nickel is u(Ni)=0.006 6 mg/kg, the extended uncertainty of cobalt is u(Co)=0.005 9 mg/kg, and the extended uncertainty of manganese is u(Mn)=0.006 5 mg/kg.

For the issue of PMMA toughened material which easily produces mold fouling and affects the manufacturing of automotive lighting, this paper proposes a mold fouling collection device which can be used to observe the precipitation of the mold fouling at different shear rates and examine composition of mold fouling by the method of Py-GCMS. In addition, 2 toughened PMMA materials are selected to study the influence of the material characteristics on the mold fouling by differential scanning calorimetry and thermogravimetric analysis. The results show that from a technological point of view the higher the shear rate due to shear heating, the higher the temperature, the more the mold fouling precipitates are produced; from the perspective of the material formulation, the lower the glass transition temperature, the lower the temperature rise under the same shear, the less the mold fouling is produced.

To address the safety concerns of Proton Exchange Membrane Fuel Cell Electric Vehicles (PEMFCEV), this paper uses the fault tree method to explore the factors affecting the safety of PEMFCEV, analyzes the potential safety hazards of proton exchange membrane fuel cell systems, power batteries and high-voltage electrical circuits, and elaborates the current domestic and foreign PEMFCEV manufacturers’ safety prevention and control strategies adopted for hydrogen leakage, power battery, and electrical safety. The results show that the current safety measures for PEMFCEV can prevent and control foreseeable safety risks.

Regarding the issue of the assembly torque of the aluminum alloy bushing of the subframe and the connecting bolts to the body of a certain model exceeding the upper limit of the monitoring window and triggering an alarm, through the analysis of the bolt assembly curve, it is found that the reason for alarm is that when the assembly torque reaches the upper limit of the monitoring window, the bolt tightening has not reached the process angle yet (this position is assembled by using the torque angle method). The comparison results between the bolt states of normal assembly and alarm show that the anti-slip teeth under the bolt head of assembly alarm is embedded in the gasket, while the anti-slip teeth of the gasket of the normal assembly bolt is embedded in the aluminum alloy bushing. The anti-slip teeth embedded in the gasket under the bolt head of the assembly alarm will drive the gasket to rotate, resulting in an increase in the friction diameter, friction coefficient of the bolt head, and assembly torque, thereby causing the assembly curve alarm. The embedding of anti-slip teeth under the bolt head into the gasket is due to insufficient heat treatment of the gasket, resulting in a softer hardness that is lower than the design required value.

In this study, the silicone-oil damper of a heavy-duty diesel engine is taken as the research object, and a linear cumulative damage model of the silicone-oil damper is developed by taking silicone-oil deterioration as a damage parameter. Based on the results of mixed cycle and load cycle durability engine bench tests, the life model of the damper is calibrated. Combined with the measured road load spectrum, the service life of the silicone-oil damper in actual usage scenarios has been predicted. The results show that under the working condition of the tractor, the predicted life of the M60 damper based on mixed cycle and load cycle tests is 1.425 million km and 2.896 million km, respectively, both of which meet the requirements for engine life mileage.

In order to analyze the influence of the adhesive layer on the surface quality during the manufacturing process of the sandwich structure, modeling and analysis are carried out in the finite element analysis software ABAQUS with PMMA as the main research object. During the hot-pressing manufacturing process of the sandwich structure, the influence of the adhesive on the surface quality is studied through the 2 processes of heating and pressurization. The results show that when only the heating process is considered, due to the viscoelasticity of the adhesive, PMMA will become softer as the temperature rises, which will lead to an increase in the surface waviness; when only the pressurization process is considered, the viscoelasticity has almost no effect on the surface waviness. When the hot-pressing is coupled, the surface waviness will be greater than that when only heating or pressurization is considered alone; the softer the adhesive, the greater the surface waviness. By adjusting the characteristics of the adhesive, the surface quality of the sandwich structure can be effectively controlled, thereby improving the overall quality of the product.

To obtain high-performance heat-treated free aluminum alloys, 3 kinds of Al-Si based heat-treated free aluminum alloys with different composition ratios are designed by adjusting the mass fractions of each element in the alloy. The melting temperature range, structure phase composition, fracture morphology, tensile and fatigue performance of 3 kind of alloys are analyzed by using Differential Scanning Calorimeter (DSC), metallographic microscope, scanning electron microscope, tensile testing machine and electromagnetic resonance fatigue testing machine. The results show that 2# alloy has good casting fluidity, metallographic structure, comprehensive strength and toughness properties and casting manufacturability, with a melting temperature range of 55 ℃, the tensile strength, yield strength and elongation rate at break are 303 MPa, 153 MPa and 11.3%, respectively. The average axial tensile compressive fatigue strength at 1×10⁷ cycles is 125 MPa, which is superior to the fatigue performance of AlSi9Cu3 (Fe) die-casting alloy commonly applied in the automotive industry.

Cooling performance of coolants with 6 different types and contents of additives is studied through cooling rate experiments. The result shows that the cooling performance of the coolants with the nonionic additive is the best, followed by the coolants with the mixed additive, and the coolants with the ionic additive exhibits the worst cooling performance. The lower the additive content, the better the cooling performance of the coolant. The cooling performance of coolant A containing 0.11% non-ionic addifive by mass is the best, with the shortest time corresponding to the probe temperature reaching 200 ℃, which is 6.1 s and the maximum cooling rate reaches 60 ℃/s.

To explore the application of micro foaming blow molding technology in automotive air ducts,this paper adjusts the blowing presstre and temperature in the production process to obtain qualified samples and rerifies their material properities and product performance. The results show that, compared with the unfoamed air duct, air duct parts with foaming ratio of 10% experience significant degrease of tensile and bending performance, with performance degradation up to 40%. In the foaming ratio range between 10% to 30%, with the increase of foaming ratio, the tensile and bending performance of the air duct material gradually decrease, but compared with tensile strength, the bending strength decreases more slowly. The air duct with foaming ratio of 30% not only meets the appearance requirements, but also meets the product performance requirements for automotive products. At the same time, by trial production of air ducts with different structures, the design points of microfoaming air duct are summarized.

In order to rapidly select the best lubricating grease for vehicles in different conditions, 4 actual vehicle working conditions are simulated including normal driving, heavy load, climbing and high speed using a four-ball machine with the wear diameter of the measured sample as evaluation index. Combined with droplet point, evaporation loss and oxidation stability, the performance of 4 long-life composite lithium based grease is studied, and the best choice of lubricating grease under different using scenarios are summarized as well.