Battery and battery preparation method

The embodiment of the invention provides a battery and a battery preparation method, the battery comprises a shell, an end cover, a cap and a battery cell, the end cover and the cap are independently arranged, the end cover is provided with a through hole, the battery cell comprises a pole core body and a pole lug connected to the pole core body, and the end cover comprises a first side and a second side which are opposite to each other; wherein the first side and the shell are connected and define a first containing cavity, the second side and the cap are connected and define a second containing cavity, and the through hole penetrates through the first containing cavity and the second containing cavity; and the pole core body and/or the pole lug are/is accommodated in the second accommodating cavity. The battery can conveniently adapt to high-energy density requirements, and the cycle life of the battery is prolonged.