Cutaway depiction of TKMS-HDWs Type 216 - its within requirement 4,000 ton displacement offers the options of, LIBs, AIP, one or more Vertical Multi-Purpose Locks (VMPL) behind the sail and/or the option of two 650+ mm Horizontal Multi-Purpose Locks (HMPL) in the bow (Diagram courtesy Submarine Dossier)
Is buying from Japan, without major defence export experience since 1938, worth the risk of another failed Australian submarine project? See COMMENT section below.
Also see an excellent article from ASPI. Submarine Matters has long been discussing the very complex issue of Lithium-ion Batteries (LIBs) in comparison with the latest AIP technology.
ASPI's Strategist published an article of March 1, 2016 by Dr John White, Chairman, TKMS Australia, entitled:
Naval shipbuilding in Australia: into the digital age:
Part of this TKMS article http://www.aspistrategist.org.au/naval-shipbuilding-in-australia-into-the-digital-age/ is: