In some examples, a battery assembly for an implantable medical device. The battery assembly may include an electrode stack comprising a plurality of electrode plates, wherein the plurality of electrode plates comprises a first electrode plate including a first tab extending from the first electrode plate and a second electrode plate including a second tab extending from the second electrode plate; a spacer between the first tab and the second tab; and a rivet extending through the first tab, second tab, and spacer, wherein the rivet is configured to mechanically attach the first tab, second tab, and spacer to each other.