What modern battery density would change in World War II

What would World War II look like if every navy had modern battery power density?

Submarines would stay submerged longer, while surface ships would gain more resilient damage-control power and perhaps wider electric propulsion.

World War II submarines could remain submerged much longer if their batteries stored energy at modern densities. That endurance would make detection and anti-submarine operations more difficult. Surface warships could also carry larger electrical reserves to preserve pumps, lighting, communications, and other damage-control functions after machinery casualties. The change might encourage more electric-drive arrangements as well as improve the survivability of existing designs.