DEVELOPMENT OF RAPID-STAMPING BATTERY SHELL STEEL USED FOR ELECTRIC VEHICLE

摘要

The battery shell steel for pure electric vehicles is a kind of high-end cold-rolling strip with high comprehensive performance requirements, such as high cleanliness, high surface quality, good property uniformity, excellent forming property and so on. As the demand for lightweight and battery life of pure electric vehicles gradually increases, the battery shell steels are required to be able to meet the requirements for thinning stamping and ensure sufficient strength after forming to avoid the occurrence of bulging defects due to insufficient compressive capacity after the battery is charged. In addition, based on the requirement of improving production efficiency, and with the progress of processing and forming equipment, it is required that the battery shell steel should be able to adapt to the requirements of rapid stamping [1]. The typical steel for battery shells generally consists of a low-carbon aluminum-killed steel component system and an ultra-low carbon IF steel component system. The former has higher strength but lower formability, while the latter tends to have excellent stamping performance but low yield strength and cannot be used for battery case manufacturing of pure electric vehicles with large internal pressure [2]. In this study, the component design and rolling process were optimized to develop a steel for battery shells of pure electric vehicles for rapid stamping. We have developed a kind of ultra-low carbon battery steel with relatively high strength and good forming property, by well designing of the chemical composition, coiling temperature of hot rolling, reduction of cold rolling and the continuous annealing process.