A top cap structure for a power battery includes a first electrode assembly and a top cap piece. The first electrode assembly includes a first electrode column and a first connection block. The first connection block includes a main body and a compound portion that are bonded together. A base metal material of the main body is different from the base metal materials of the first electrode column and the compound portion. The compound portion includes a first connection hole and the main body includes a second connection hole. A top portion of the first electrode column includes a connection section. The connection section passes through the top cap piece, the second connection hole, and the first connection hole, and extends from the first connection hole. The connection section and the compound portion are welded together. The connection section is riveted to the second connection hole.