Teammates can't get damaged directly by any grenades thrown or launched by a player, they may get thrown around (in some instances quite extremely), but not hurt by the explosion itself.
The person who threw it, however, can be hurt by the explosion, albeit the damage received by that player is reduced.
This acts as a deterrent to people in close-quarters combat from just dropping a grenade at their feet, blowing everyone to kingdom come, and then walking out none the worse.
The knockback received isn't supposed to be a method of transport... and I'd argue that it's so unpredictable that it realistically can't be used as such.
However if you have the health potions for it, go for it! ;)
My advice, though, would be if you want to get up to somewhere; build. If you want to get across a gap; build. :p