A battery assembly comprising: a first housing shell (102) having a first perimeter side wall (102a), a first housing bottom (102b), and a first contact area (113a) on said first housing bottom； a second housing shell (104) having a second perimeter side wall (104a), a second housing bottom (104b), and a second contact area (113b) on said second housing bottom, said second housing shell being disposed in said first housing shell with said second contact area opposing said first contact area； an insulator (110) interposed between said first housing shell and said second housing shell to effect electrical insulation between said first housing shell and said second housing shell； and battery components comprising: an anode electrode (132) electrically communicated to one of said first contact area or said second contact area； a cathode electrode (130) electrically communicated to another one of said first contact area or said second contact area； and a separator (131) interposed between said cathode electrode and said anode electrode, said separator including an electrolyte.
