Flexible polymer laminates for use in battery housings, battery housings made from the laminates, and batteries made from battery cells enclosed within the housings. In one embodiment the laminate is comprised of a barrier polymer sheet with a heat-sealable polymer frame. In other embodiments the laminate is a film of a barrier polymer in contact with a heat-sealable polymer. In various embodiments the barrier polymer is a polyester and the heat-sealable polymer is a polyolefin.