No in one of the episodes in the manga,episode 660 something I can't remember he achieved bankai,his bankai is a big sword.
i know what your thinking it was shikia his sword never went into the true form cause he was not harmonizing with it and never new it name. shikia can only manifest if you know the name and you have a bond with it.
Shikai: Its release command is
Drink (呑め,
nome).
[168] Even before Kenpachi knew its name,
Nozarashi was constantly in its released state, due instead to Kenpachi's overwhelming Reiatsu forcing the release.
[169] He obtained this state while still a child.
[170] The blade is much longer than a standard Zanpakutō's, roughly the size of a
nodachi, with a guard which extends inward from its center, similar to a shinai. The hilt is white, though most of it is wrapped in bandages, as is his sword's sheath. Despite constantly being in Shikai,
Nozarashi did not initially grant Kenpachi any additional abilities or possess any additional power of its own, due to their lack of communication.
[171] Their disharmony left
Nozarashi with little spiritual energy and let it become easier to damage; it is a chipped and seemingly worn-down blade. Despite its appearance,
Nozarashi can easily cut through most objects: with it, Kenpachi stabs straight through Ichigo's Zanpakutō, and later slices a building in half with no apparent effort after releasing his full power. However, upon Kenpachi calling out its release command,
Nozarashi transforms into a huge axe with a long, cloth-wrapped handle and a tassel attached to the top.
that explains the mistake
http://bleach.wikia.com/wiki/Kenpachi_Zaraki
