BOX BODY APPLIED TO BATTERY, BATTERY ASSEMBLY, ELECTRIC APPARATUS, AND METHOD AND DEVICE FOR PREPARING BATTERY ASSEMBLY

A box body includes a carrying plate configured to carry a battery and a one-way gravity valve disposed at the carrying plate. The one-way gravity valve is configured to be closed in response to a gravity of liquid in the box body being less than a threshold, and to be open in response to the gravity of the liquid in the box body reaching the threshold.