A cell separation device configured for separating cells from microcarriers or spheroids in a liquid is provided. The cell separation device includes a vessel comprising a first port, a second port, and a cavity; and a porous mesh disposed within the cavity to divide the cavity into a first compartment and a second compartment, wherein the first port is in communication with the first compartment of the cavity, the first port located to a first side of the porous mesh, wherein the second port is in communication with the second compartment of the cavity, the second port located to a second side of the porous mesh, and wherein the porous mesh is positioned within the cavity to have a substantially vertical orientation or an inclined orientation with respect to a flow of liquid through the porous mesh.