电池
diànchí · HSK 5
battery
🔋 电 (electric) + 池 (pool) = electric pool, i.e. battery
池 literally means pond or pool — a container holding something. So 电池 is an electric pool, a vessel holding electricity. Same logic as 水池 (water pool) and 游泳池 (swimming pool).
电 — rain 雨 + lightning tail 电
Originally a pictograph of lightning streaking from a cloud, written 電 with the rain radical 雨 on top. The bottom 电 depicts the zigzag flash itself. The simplified form 电 drops 雨 and keeps just the lightning shape. Meaning extended from 'lightning' to 'electricity' in modern usage.