A leadless cardiac pacemaker that does not require a separate hermetic housing surrounding the battery and electronics compartments is provided. The cardiac pacemaker can include a battery disposed in a battery housing and a set of electronics disposed in an electronics housing. In some embodiments, the battery housing and the electronics housing can comprise an external surface of the pacemaker. The pacemaker can include a first set of welds separating the battery from the set of electronics, and a second set of welds separating the set of electronics and the battery from an exterior of the housing. Various embodiments for achieving dual-redundant welds are also provided.