Extruded hollow plate, battery box bottom plate, battery casing, and electric vehicle

A battery box bottom plate, formed by splicing extruded hollow plates, wherein:

• the extruded hollow plate comprises a plate-shaped body having a constant cross section, the plate-shaped body comprises a cavity inside, the body comprises a protrusion and/or a groove at end portions or at an end portion, the protrusion bends downward, the groove forms an upward hook at an opening thereof, the protrusion comprises a first curved surface, a first transitional surface, and a third curved surface, the groove comprises a second curved surface, a second transitional surface, and a fourth curved surface, and the first curved surface, the second curved surface, the third curved surface, and the fourth curved surface comprise at least two involute surfaces;
• when two extruded hollow plates are spliced, a structural adhesive is applied to a surface of a groove of one of the extruded hollow plates, and a protrusion of the other extruded hollow plate is rotated with a lower-surface seam as a center and inserted into the groove;
• in the rotation and insertion process, a first gap is kept between the first curved surface and the second curved surface, and a second gap is kept between the third curved surface and the fourth curved surface;
• when the first transitional surface overlaps the second transitional surface, the two hollow plates are flush with each other at an upper-surface seam;
• a first bonding layer of 0.1 to 0.2 mm is evenly applied into the first gap, and a wedge-shaped second bonding layer is formed inside the second gap;
• the second gap is wedge-shaped, and when the protrusion is rotated into the groove, the structural adhesive coated on a joint interface is evenly squeezed by the wedge-shaped gap that the structural adhesive gradually enters, and finally, an evenly spread bonding layer is formed inside the wedge-shaped gap;
• and
• the protrusion comprises a recess at a root portion thereof and between the first curved surface and the end portion of the body, and the groove comprises a downward hook at a top portion thereof and between the second curved surface and the end portion of the body;
• when the two extruded hollow plates are spliced, the downward hook is squeezed into the recess for providing reverse locking;
• and the groove comprises, at the opening thereof, a deformation portion used for connecting the protrusion in a pressed manner, and after the protrusion is mounted into the groove, the deformation portion is squeezed by an external force to contract.

A battery shell, formed by side plates and a bottom plate, wherein:

• the bottom plate is formed by splicing extruded hollow plates, the extruded hollow plate comprises a plate-shaped body having a constant cross section, the plate-shaped body comprises a cavity inside, the body comprises a protrusion and/or a groove at end portions or at an end portion, the protrusion bends downward, the groove forms an upward hook at an opening thereof, the protrusion comprises a first curved surface, a first transitional surface, and a third curved surface, the groove comprises a second curved surface, a second transitional surface, and a fourth curved surface, and the first curved surface, the second curved surface, the third curved surface, and the fourth curved surface comprise at least two involute surfaces;
• when two extruded hollow plates are spliced, a structural adhesive is applied to a surface of a groove of one of the extruded hollow plates, and a protrusion of the other extruded hollow plate is rotated with a lower-surface seam as a center and inserted into the groove;
• in the rotation and insertion process, a first gap is kept between the first curved surface and the second curved surface, and a second gap is kept between the third curved surface and the fourth curved surface;
• when the first transitional surface overlaps the second transitional surface, the two hollow plates are flush with each other at an upper-surface seam;
• a first bonding layer of 0.1 to 0.2 mm is evenly applied into the first gap, and a wedge-shaped second bonding layer is formed inside the second gap;
• the second gap is wedge-shaped, and when the protrusion is rotated into the groove, the structural adhesive coated on a joint interface is evenly squeezed by the wedge-shaped gap that the structural adhesive gradually enters, and finally, an evenly spread bonding layer is formed inside the wedge-shaped gap;
• and
• the protrusion comprises a recess at a root portion thereof and between the first curved surface and the end portion of the body, and the groove comprises a downward hook at a top portion thereof and between the second curved surface and the end portion of the body;
• when the two extruded hollow plates are spliced, the downward hook is squeezed into the recess for providing reverse locking;
• and the groove comprises, at the opening thereof, a deformation portion used for connecting the protrusion in a pressed manner, and after the protrusion is mounted into the groove, the deformation portion is squeezed by an external force to contract.