Battery Housing Recessed Joint for Precise Welding Alignment

The patent applies preliminary action by providing positioning structures (positioning grooves and positioning protrusions) on the lower shell and upper cover respectively, before the welding process. These positioning structures are formed during the stamping process, ensuring that when the upper cover is placed on the lower shell, they automatically align and fix the relative position, preventing movement during welding and ensuring dimensional precision without requiring complex welding fixtures.

The patent applies spheroidality by using arc-shaped reinforcement ribs instead of traditional rounded corners at the joints between the bottom plate and side frames. These arc-shaped ribs provide structural reinforcement similar to rounded corners but with a more space-efficient design that minimizes volume loss while maintaining joint strength. The arc shape distributes stress effectively while occupying less space compared to full rounded corners.

The patent applies the taking out principle by completely removing the flange edge structure from the battery housing design. Instead of having a flange edge that requires cutting, the upper cover and lower shell are directly connected through welding with positioning structures that ensure precise alignment. This eliminates the need for post-manufacturing cutting operations, avoiding quality and precision issues associated with cutting while still enabling proper battery installation.