SHELL ASSEMBLY FOR BATTERY AND POWER DEVICE

Provided are a shell assembly for a battery, a battery, and a power device. The shell assembly includes: a shell, where a first mating surface and a first end surface are formed on an end portion of the shell, and an included angle between the first mating surface and the first end surface is α; and a cover plate, where the cover plate covers the end portion of the shell and forms a first surface, a protruding portion protruding toward an interior of the shell is formed on the first surface, and a second mating surface adapted to abut against the first mating surface is formed on the protruding portion. An included angle between the second mating surface and the first surface is α, and α and α satisfy: α and α