import bpy, bmesh
from bpy import context
from  mathutils import Vector
# bounding box helper methods
def bbox(ob):
    return (Vector(b) for b in ob.bound_box)

def bbox_center(ob):
    return sum(bbox(ob), Vector()) / 8

def bbox_axes(ob):
    bb = list(bbox(ob))
    return tuple(bb[i] for i in (0, 4, 3, 1))

def slice(bm, start, end, segments):
    if segments == 1:
        return
    def geom(bm):
        return bm.verts[:] + bm.edges[:] + bm.faces[:]
    planes = [start.lerp(end, f / segments) for f in range(1, segments)]
    #p0 = start
    plane_no = (end - start).normalized()
    while(planes):
        p0 = planes.pop(0)
        ret = bmesh.ops.bisect_plane(bm,
                geom=geom(bm),
                plane_co=p0,
                plane_no=plane_no)
        bmesh.ops.split_edges(bm,
                edges=[e for e in ret['geom_cut']
                if isinstance(e, bmesh.types.BMEdge)])


bm = bmesh.new()
ob = context.object
me = ob.data
bm.from_mesh(me)

o, x, y, z = bbox_axes(ob)

x_segments = 2
y_segments = 2
z_segments = 1

slice(bm, o, x, x_segments)
slice(bm, o, y, y_segments)
slice(bm, o, z, z_segments)
bm.to_mesh(me)

bpy.ops.object.mode_set(mode='EDIT')
bpy.ops.mesh.separate(type='LOOSE')
bpy.ops.object.mode_set()

>>> C.object.location
Vector((644784.5, 4979532.0, 0.0))

>>> v = C.object.location.copy()
>>> for o in C.selected_objects:
...     o.location -= v