A portable electronic device is described. This portable electronic device includes an external housing with a cavity defined by an edge. A keyboard, having a front surface and a back surface, is disposed in the cavity with the front surface facing the external housing. Moreover, a tray is disposed over the back surface of the keyboard, and is mechanically coupled to the external housing adjacent to the edge. Furthermore, battery cells are mechanically coupled to an opposite side of the tray from the back surface of the keyboard. The tray may allow the battery cells to be removed from the portable electronic device without damaging the keyboard. In addition, the tray may increase the compression strength and/or the bending strength of the portable electronic device.