One embodiment of the present subject matter includes a battery having a stack of substantially planar battery electrodes, the stack including a first electrode including a first tab, and a second electrode including a second tab, with the first tab electrically connected to the second tab. The embodiment includes a first separator layer and a second separator layer sandwiching the first electrode, with the edges of the first separator layer and the second separator connected with a weld, the first separator layer and the second separator layer defining an interior space in which the first electrode is disposed, with the first tab extending outside the interior space. The embodiment includes an battery housing having electrolyte disposed therein, the housing including at least a first aperture and a feedthrough aperture; a lid conformed and sealed to the first aperture; and a feedthrough conformed and sealed to the feedthrough aperture.