Battery parts having retaining and sealing features and associated assemblies and methods are disclosed herein. In one embodiment, a battery part includes a base portion that is configured to be embedded in battery container material of a corresponding battery container. The battery part and base portion include several torque resisting features and gripping features that resist torsional or twist loads that are applied to the battery part after it has been joined to the battery container. For example, the base portion can include several internal and external torque resisting features and gripping features that are configured to resist twisting or loosening of the battery part with reference to the battery container material, as well as prevent or inhibit fluid leakage from the battery container.