The present disclosure relates to composite battery covers including one or more integral vent members configured to release pressure. An example composite battery cover includes a continuous sheet having a first stiffness and one or more vent members defined in the continuous sheet. Each of the one or more vent members may include a first area having a second stiffness and/or a second area having a third stiffness. The second stiffness may be different from the first stiffness. The third stiffness may be different from the second stiffness and/or the first stiffness. The stiffness and strength of the continuous sheet and/or one or more vent members may be controlled by variable thicknesses and/or fiber loadings.