The batteries are designed to be leak-proof and hermetically sealed.
电池的设计防渗漏,密封性很好。
2ADJ-GRADED 与外界隔绝的;不受外界干扰的 You use hermetic to describe something which you disapprove of because it seems to be totally separate from other people and things in society. 与外界隔绝的;不受外界干扰的 [written, disapproval]
Its film industry operates in its own curiously hermetic way.