Battery dimensions are same as CATL's 587 Ah lithium storage cell:

Length 73.5mm

Width 286mm

Height 216mm

Apparently dimensions for the lithium cell were designed based on constraints: maritime transport weight limits (50t), 1500V max system voltage ceiling, 20-foot container (turn key system - image https://www.ess-news.com/2025/04/16/hithium-unveils-587-ah-c... ).

I assume the Sodium cells are heavier but they chose the same cell size for physical backwards compatibility.