A kink-free semiconductor optical device stabilizing laser oscillation and producing a high optical performance. Commercially available valves which operate by electrical, hydraulic or pneumatic means are often expensive and bulky. In various embodiments of the present invention, the plurality of wall portions include a plurality of radiating sections with varying geometric shapes. Each aerator is disposed inside the storage bin having a substantially vertical orientation and mounted to an inside surface of a wall of the storage bin such that the aerator is structurally supported by the wall. The capacity of the lithium secondary battery may substantially be recovered after being left at a high temperature.