High voltage battery unit for vehicle and underbody of vehicle

An underbody of a vehicle, comprising:

• a center floor forming a lower portion of a vehicle;
• a high voltage battery unit including battery built-in parts coupled at both sides under the center floor, respectively and having a high voltage battery built-in therein, and a connecting portion configured to connect between the battery built-in parts, to form an installation space in a front and rear direction of the vehicle, and to allow a drive shaft of the vehicle to penetrate between the battery built-in parts of both sides thereof through the installation space;
• and
• a front cross member positioned at a front of the high voltage battery unit, extending in a left and right direction of the vehicle, and coupled to the center floor,
• wherein the front cross member forms a load path by connecting side sills positioned at left and right sides of the vehicle.