Power storage device packaging material

1. A power storage device packaging material, comprising:

a substrate layer, which is a polyamide film,

an aluminum foil layer having an anticorrosion treatment layer on both sides thereof, and a sealant layer in this order,

wherein the sealant layer is in direct physical contact with the anticorrosion treatment layer on the aluminum foil layer;

the sealant layer includes a propylene-based branched polymer-containing layer that consists of (a) a propylene-based branched polymer having branched chains and (b) a first base resin composition consisting of (AR-1) a random polypropylene based acid-modified polypropylene resin composition and (AR-2) a propylene-α-olefin copolymer having an atactic structure, wherein a ratio of (AR-1) to (AR-2) is 75:25,

wherein the propylene-based branched polymer does not have a crosslinked structure, wherein the propylene-based branched polymer is selected from the group consisting of:

(A) a propylene-ethylene random copolymer with branched chains having 500 or more carbons;

(B) a propylene-1-butene copolymer with branched chains having 500 or more carbons;

(C) a homopolypropylene with branched chains having 500 or more carbons; and

(D) a block polypropylene with branched chains having 500 or more carbons;

wherein the substrate layer is an outermost layer of the power storage device packaging material and the sealant layer is an innermost layer of the power storage device packaging material; and

wherein the sealant layer consists of the propylene-based branched polymer-containing layer and a second layer, the propylene-based branched polymer-containing layer is in direct physical contact with the anticorrosion treatment layer on the aluminum foil layer, wherein a mass content of the propylene-based branched polymer in the propylene-based branched polymer-containing layer is from 1 mass % to 10 mass %, the second layer of the sealant layer comprises a second resin composition prepared by mixing (A-1) a propylene-ethylene random copolymer having a melting temperature from 125° C. to 140° C., (B-1) a propylene-1-butene random copolymer elastomer having a melting temperature from 65° C. to 90° C. and (B-2) an ethylene-1-butene random copolymer elastomer having a melting temperature from 65° C. to 90° C. at a mass ratio of (A-1):(B-1):(B-2)=70:20:10; and the anticorrosion treatment layer comprises sodium polyphosphate stabilized cerium oxide sol having a solid content concentration of 10 mass % and a mixture of 90 mass % of polyallylamine and 10 mass % of polyglycerol polyglycidyl ether, wherein the mixture has a solid concentration of 5 mass %.

2. The power storage device packaging material of claim 1 , wherein the propylene-based branched polymer is the propylene-ethylene random copolymer with branched chains having 500 or more carbons.

3. The power storage device packaging material of claim 1 , wherein the propylene-based branched polymer is the propylene-1-butene copolymer with branched chains having 500 or more carbons.

4. The power storage device packaging material of claim 1 , wherein the propylene-based branched polymer is the homopolypropylene with branched chains having 500 or more carbons.

5. The power storage device packaging material of claim 1 , wherein the propylene-based branched polymer is the block polypropylene with branched chains having 500 or more carbons.

6. The power storage device packaging material of claim 1 , wherein the second layer of the sealant layer consists of the second resin composition.

7. The power storage device packaging material of claim 1 , wherein the second layer of the sealant layer further comprises 2 mass % to 75 mass % of a second propylene-based branched polymer selected from the group consisting of:

(A) a propylene-ethylene random copolymer with branched chains having 500 or more carbons;

(B) a propylene-1-butene copolymer with branched chains having 500 or more carbons;

(C) a homopolypropylene with branched chains having 500 or more carbons; and

(D) a block polypropylene with branched chains having 500 or more carbons.

8. A power storage device packaging material, comprising:

a substrate layer, which is a polyamide film,

an aluminum foil layer having an anticorrosion treatment layer on both sides thereof, and a sealant layer in this order,

wherein the sealant layer is in direct physical contact with the anticorrosion treatment layer on the aluminum foil layer;

the sealant layer includes a propylene-based branched polymer-containing layer that consists of (a) a propylene-based branched polymer having branched chains and (b) a first base resin composition consisting of (AR-1) a random polypropylene based acid-modified polypropylene resin composition and (AR-2) a propylene-α-olefin copolymer having an atactic structure, wherein a ratio of (AR-1) to (AR-2) is 75:25,

wherein the propylene-based branched polymer does not have a crosslinked structure, wherein the propylene-based branched polymer is selected from the group consisting of:

(A) a propylene-ethylene random copolymer with branched chains having 500 or more carbons;

(B) a propylene-1-butene copolymer with branched chains having 500 or more carbons;

(C) a homopolypropylene with branched chains having 500 or more carbons; and

(D) a block polypropylene with branched chains having 500 or more carbons;

wherein the substrate layer is an outermost layer of the power storage device packaging material and the sealant layer is an innermost layer of the power storage device packaging material; and

wherein the sealant layer consists of the propylene-based branched polymer-containing layer, a third layer and a second layer between the propylene-based branched polymer-containing layer and the third layer; the propylene-based branched polymer-containing layer is in direct physical contact with the anticorrosion treatment layer on the aluminum foil layer, wherein a mass content of the propylene-based branched polymer in the propylene-based branched polymer-containing layer is from 1 mass % to 10 mass %, each of the second layer and the third layer of the sealant layer comprises a second resin composition prepared by mixing (A-1) a propylene-ethylene random copolymer having a melting temperature from 125° C. to 140° C., (B-1) a propylene-1-butene random copolymer elastomer having a melting temperature from 65° C. to 90° C. and (B-2) an ethylene-1-butene random copolymer elastomer having a melting temperature from 65° C. to 90° C. at a mass ratio of (A-1):(B-1):(B-2)=70:20:10; one of the second layer and the third layer of the sealant layer further comprises a second propylene-based branched polymer selected from the group consisting of:

(A) a propylene-ethylene random copolymer with branched chains having 500 or more carbons;

(B) a propylene-1-butene copolymer with branched chains having 500 or more carbons;

(C) a homopolypropylene with branched chains having 500 or more carbons; and

(D) a block polypropylene with branched chains having 500 or more carbons;

the other of the second layer and the third layer of the sealant layer consists of the second resin composition and the anticorrosion treatment layer comprises sodium polyphosphate stabilized cerium oxide sol having a solid content concentration of 10 mass %, and a mixture of 90 mass % of polyallylamine and 10 mass % of polyglycerol polyglycidyl ether, wherein the mixture has a solid concentration of 5 mass %.

9. The power storage device packaging material of claim 8 , wherein the second layer of the sealant layer consists of the second resin composition and the third layer of the sealant layer further comprises 6 mass % of the propylene-ethylene random copolymer with branched chains having 500 or more carbons.

10. The power storage device packaging material of claim 8 , wherein the third layer of the sealant layer consists of the second resin composition and the second layer of the sealant layer further comprises 6 mass % of the propylene-ethylene random copolymer with branched chains having 500 or more carbons.