Battery packaging material
Provided is a battery packaging material comprising a film-like layered body obtained by sequentially layering at least a substrate layer, an adhesive layer, a metal layer and a sealant layer, the battery packaging material exhibiting excellent moldability and being unlikely to crack or form a pinhole during the molding thereof. A battery packaging material comprising a layered body obtained by sequentially layering at least a substrate layer, an adhesive layer, a metal layer and a sealant layer, wherein the substrate layer is configured in a manner such that the sum (A+B) of a value (A) equal to stress when stretching to 50% in the MD direction/stress when stretching to 5% and a value (B) equal to stress when stretching to 50% in the TD direction/stress when stretching to 5% satisfies the relationship A+B≥3.5.
1. A battery packaging material comprising a laminate in which at least a base material layer, an adhesive layer, a metal layer and a sealant layer are laminated in this order,
the base material layer satisfying the relationship of A+B≥3.5, where A+B is a sum of a value A of a ratio of a stress in elongation by 50% in the MD direction to a stress in elongation by 5% in the MD direction and a value B of a ratio of a stress in elongation by 50% in the TD direction to a stress in elongation by 5% in the TD direction.
2. The battery packaging material according to claim 1 , wherein the value A and the value B satisfy the relationship of A<B.
3. The battery packaging material according to claim 1 , wherein the value A is 1.5 or more, and the value B is 2.0 or more.
4. The battery packaging material according to claim 1 , wherein the base material layer is formed of at least one of a polyamide resin and a polyester resin.
5. The battery packaging material according to claim 1 , wherein at least one surface of the metal layer is subjected to a chemical conversion treatment.
6. The battery packaging material according to claim 1 , wherein the metal layer is formed of an aluminum foil.
7. The battery packaging material according to claim 1 , which is a packaging material for a secondary battery.
8. A battery comprising a battery element which includes at least a positive electrode, a negative electrode and an electrolyte, the battery element being stored in the battery packaging material according to claim 1 .
9. A method to be applied to a battery packaging material, of a laminate in which at least a base material layer, an adhesive layer, a metal layer and a sealant layer are laminated in this order,
the base material layer satisfying the relationship of A+B≥3.5, where A+B is a sum of a value A of a ratio of a stress in elongation by 50% in the MD direction to a stress in elongation by 5% in the MD direction and a value B of a ratio of a stress in elongation by 50% in the TD direction to a stress in elongation by 5% in the TD direction.
10. A method for producing a battery,
the method comprising the step of: storing in a battery packaging material a battery element including at least a positive electrode, a negative electrode and an electrolyte,
the battery packaging material including
a laminate in which at least a base material layer, an adhesive layer, a metal layer and a sealant layer are laminated in this order,
the base material layer satisfying the relationship of A+B≥3.5, where A+B is a sum of a value A of a ratio of a stress in elongation by 50% in the MD direction to a stress in elongation by 5% in the MD direction and a value B of a ratio of a stress in elongation by 50% in the TD direction to a stress in elongation by 5% in the TD direction.