A battery assembly comprising: a first housing shell having a first perimeter side wall , a first housing bottom , and a first contact area on said first housing bottom ; a second housing shell having a second perimeter side wall , a second housing bottom , and a second contact area 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 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 electrically communicated to one of said first contact area or said second contact area; a cathode electrode electrically communicated to another one of said first contact area or said second contact area; and a separator interposed between said cathode electrode and said anode electrode, said separator including an electrolyte; wherein said first housing bottom of said first housing shell opposes said second housing bottom of said second housing shell to define a battery component cavity in conjunction with said first perimeter side wall of said first housing shell , and said anode electrode, said separator, and said cathode electrode are disposed in said battery component cavity ; characterized in that said second perimeter side wall includes a U-fold extending from a junction with said second housing bottom toward said first housing bottom and defines at least a portion of said battery components cavity; wherein said U-fold has first and second opposite outer surfaces and said insulator is disposed on said first and second opposite outer surfaces. a first housing shell having a first perimeter side wall , a first housing bottom , and a first contact area on said first housing bottom ; a second housing shell having a second perimeter side wall , a second housing bottom , and a second contact area 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 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 electrically communicated to one of said first contact area or said second contact area; a cathode electrode electrically communicated to another one of said first contact area or said second contact area; and a separator interposed between said cathode electrode and said anode electrode, said separator including an electrolyte; wherein said first housing bottom of said first housing shell opposes said second housing bottom of said second housing shell to define a battery component cavity in conjunction with said first perimeter side wall of said first housing shell , and said anode electrode, said separator, and said cathode electrode are disposed in said battery component cavity ; characterized in that said second perimeter side wall includes a U-fold extending from a junction with said second housing bottom toward said first housing bottom and defines at least a portion of said battery components cavity; wherein said U-fold has first and second opposite outer surfaces and said insulator is disposed on said first and second opposite outer surfaces. <EOS>