Abstract: A lithium ion battery and an electric vehicle with the same are provided. The lithium ion battery includes a cover plate assembly and a battery cell assembly, the cover plate assembly includes a pole and a polarity connecting piece, the pole is connected with the polarity connecting piece, the battery cell assembly is provided with a battery cell tab assembly, and the pole is connected and conducted with the battery cell tab assembly through the polarity connecting piece. As a hard connection, the polarity connecting piece is directly or indirectly connected with the battery cell tab assembly. The polarity connecting piece is in interference fit with the pole for laser welding, so that the connection reliability is high, the overcurrent capability is strong, and electronic conduction is easy.

Abstract: The disclosure provides a cover plate assembly for a battery and a battery device. The cover plate assembly for the battery includes a top cover; a conductive structure arranged on the top cover, the conductive structures including at least one pole for conducting electricity; at least one connection structure, a first end of each connection structure being electrically connected to a corresponding pole, a second end of the each connection structure being electrically connected to a tab of a cell, and the second end of the each connection structure being provided with an installation hole; and a locking structure including at least one locking member, each locking member penetrating the tab to be fixedly connected to the installation hole, to lock the tab on the connection structure.