Electronic cigarette for convenient injection of cigarette liquid, manufacturing method thereof, and cigarette liquid injection method thereof

An electronic cigarette for convenient injection of cigarette liquid, comprising a mouthpiece cap, a liquid storage cup, a vaporizing assembly, and a battery assembly, wherein:

• a liquid injection hole is opened at a bottom of the liquid storage cup;
• and
• the liquid injection hole is sealed by a sealing element which is self-closing once an injection device has been pulled out from the sealing element;
• the bottom of the liquid storage cup is concaved to form a cavity;
• the liquid injection hole is a through-hole opened at a center of a bottom wall of the cavity;
• a wall of the liquid injection hole is protruded towards an interior of the liquid storage cup to form a protrusion;
• the sealing element has an I-shaped cross section, the sealing element consists of a top portion, a bottom portion, a neck portion connecting the top portion to the bottom portion, and a circular recess formed between the top portion and the bottom portion;
• the protrusion of the wall of the liquid injection hole is snap-fitted into the circular recess of the sealing element;
• wherein the mouthpiece cap consists of:
• a mouth-contacting piece having an extension portion and an opening, the extension portion being arranged on a mouth portion of a shell of the electronic cigarette, the opening being opened at a center of the mouth-contacting piece;
• an outer tubular neck and an inner tubular neck that are protruded perpendicularly from a surface of the mouth-contacting piece and are concentrically nested, axes of the outer tubular neck and the inner tubular neck passing through a center of a circumference of the mouth-contacting piece, an end surface of the inner tubular neck being pressed against the sealing element;
• and
• four grooves uniformly spaced in the inner tubular neck;
• wherein a vapor-flow passage comprises an annulus formed between the outer tubular neck and the inner tubular neck, said four grooves, and the opening.