Abstract: A prelithiated negative electrode, and a secondary battery including a prelithiated electrode, including a negative electrode current collector; and a negative electrode active material layer present on at least one surface of the negative electrode current collector. The negative electrode active material layer includes high-capacity artificial graphite having no carbon coating. The negative electrode active material layer is prelithiated, and the content of lithium intercalated to the prelithiated negative electrode active material layer is 3% to 5% based on the lithium content intercalated when the negative electrode is charged to 100%.

Abstract: An apparatus and method for distinguishing between tack-welding and welding are provided. The apparatus for distinguishing between tack-welding and welding includes: a current sensor configured to detect arc current of a welder; and a distinguish control unit configured to distinguish whether a welding operation performed by the welder is tack-welding or welding based on the arc current detected by the current sensor for a predefined period of time. Accordingly, the amount of work performed by a welding worker can be fairly and accurately evaluated.

Abstract: Provided are a system and a method for monitoring welding operations. The system includes a welding machine, a current sensor sensing an operation time of the welding machine and a welding current, a welding information database storing information of the operation time of the welding machine and the welding current for each welding operator and storing information of a consumed charge amount of the welding machine, which is preset for each welding operation process, a data analyzer checking a charge amount consumed for the operation time by using the sensed operation time of the welding machine and the welding current and determining whether the welding operator achieves a task goal of a corresponding process by comparing the checked consumed charge amount with the preset consumed charge amount for a process performed by the welding machine, and a display unit outputting a result of the determining, performed by the data analyzer, whether the welding operator achieves a task goal of a corresponding process.