battery pack or foil pack may be based on a lithium chemistry or other suitable battery chemistry to prevent damage such as scratches or punctures foil battery pack 20 may be mounted within protective battery structures such as elastomeric battery protection structures 36 structures 36 may be formed from insulating materials such silicone polycarbonate or other plastics as an example in the illustrative configuration of fig3 battery protection structures 36 have a ring shape with vertical walls and a rectangular interior opening that receives battery pack 20 by using an elastomeric material to form some or all of structures 36 structures 36 can be stretched to fit over battery pack 20 during assembly structures 36 may also be stretched to remove structure 36 should rework be required by using a shape for battery protection structure 36 that does not fully enclose all six sides of battery pack e g a shape that leaves the opposing upper and lower rectangular faces of rectangular battery pack 20 exposed the amount of volume that is occupied by structures 36 can be minimized a two shot plastic molding process may be used in forming battery protection structures 36 the first shot of plastic may be a harder structure such as hard plastic structures 40 e g a hard plastic structure formed form a material such as polycarbonate nylon or other plastic that is relatively hard u2014 at least compared to the softer portions of structures 36.