TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Process: The battery packaging material is operated so that the inner bag is cleaved and transferred to the opening state, after an inner bag is formed in the portion in which peeling is produced. In the battery packaging material, peeling is produced in interface of the metal layer and the sealant layer, the interface of the metal layer and the contact bonding layer, the interface of the contact bonding layer and the sealant layer, and/or inside the contact bonding layer and the sealant layer. The packaging material is not opened until it reaches T degrees C, when it heats up to preset temperature of T degrees C, which is preferably 100-160 degrees C, but a packaging material is opened after reaching T degrees C rapidly. Preferred Composition: The battery packaging material further contains a contact bonding layer (2) between the base material layer and the metal layer, and contact bonding layer between the metal layer and the sealant layer. The laminate comprises a base material layer, metal layer, insulating layer, and sealant layer in order. Preferred Properties: The laminate strength in between the metal layer and the sealant layer is more than three (N/15mm) at 25 degrees C, more than 2.5 (N/15mm) at 80 degrees C, and below 2.5 (N/15mm) at 125 degrees C. The seal strength of the portion heat-sealed in the state in which the sealant layers are made to oppose is more than 30 (N/15mm) at 25 degrees C, and below 20 (N/15mm) at 125 degrees C. The bag-like packaging material is obtained by heat-sealing in the state in which the sealant layers are made to oppose. The seal strength of the heat-sealed portion after leaving the battery packaging material to stand at 85 degrees C to the interior space of the bag-like packaging material for 24 hours by the state containing electrolyte solution is more than 0.2 (N/15mm).    TECHNOLOGY FOCUS - POLYMERS - Preferred Composition: The sealant layer comprises sealant layer (S1) containing acid-modified polyolefin located in the metal layer side, sealant layer (S2) containing polyolefin located in innermost layer, which are laminated. The sealant layer (S1) contains polyethylene and/or acid-modified polyethylene, and ethylene-vinyl acetate copolymer, acrylic resin, styrene polymer, and terpene phenol resin. The insulating layer is formed of the resin composition containing acid-modified polyolefin resin and a curing agent. Preferred Process: The difference of preset temperature (T) and melting point (Tm1) of sealant layer (S1) is -10 to -5, and the difference of preset temperature (T) and melting point (Tm2) of sealant layer (S2) is -5 to 5. The sealant layer further comprises sealant layer (S3) containing polyolefin, located in the inner most layer. The difference of preset temperature (T) and melting point (Tm2) of sealant layer (S2) is 5 to 10. The difference of preset temperature (T) and melting point (Tm3) of sealant layer (S3) is -5 to 5. The sealant layer (S1) has melting point of 100-160 degrees C, and softening point of 60-150 degrees C. The difference of preset temperature (T) and melting point (Ta) of insulating layer is -10 to -5. The difference of preset temperature (T) and melting point (Tm1) of sealant layer (S1) is -5 to 5.