Thin battery and battery-mounted device

1. A thin battery comprising:

a sheet-like electrode assembly;

a non-aqueous electrolyte with which the electrode assembly is impregnated; and

a housing for housing the electrode assembly and the non-aqueous electrolyte in a sealed manner,

wherein the electrode assembly includes a pair of first electrodes disposed at outermost sides of the electrode assembly, a second electrode disposed between the pair of first electrodes, and a separator disposed between each of the first electrodes and the second electrode,

each of the first electrodes includes a first current collector sheet and a first active material layer attached to one surface of the first current collector sheet,

the second electrode has a polarity different from a polarity of the first electrode, and includes a second current collector sheet and second active material layers attached to both surfaces of the second current collector sheet, and

a content x of the non-aqueous electrolyte per unit area of the first active material layer is larger than a content y of the non-aqueous electrolyte per unit area of each of the second active material layers.

2. The thin battery of claim 1 , wherein the content x of the non-aqueous electrolyte per unit area of the first active material layer and the content y of the non-aqueous electrolyte per unit area of each of the second active material layers satisfy: 1.1≤x/y≤8.

3. The thin battery of claim 1 , wherein the second electrode comprises two or more second electrodes, and

the thin battery further comprises one or more third electrodes disposed between a pair of the second electrodes,

wherein each of the one or more third electrodes has a polarity identical to the polarity of the first electrode, and includes a third current collector sheet and third active material layers attached to both surfaces of the third current collector sheet, and

the content x of the non-aqueous electrolyte per unit area of the first active material layer is larger than or equal to a content z of the non-aqueous electrolyte per unit area of each of the third active material layers.

4. The thin battery of claim 3 , wherein the content z of the non-aqueous electrolyte per unit area of each of the third active material layers is larger than the content y of the non-aqueous electrolyte per unit area of each of the second active material layers.

5. The thin battery of claim 3 , wherein the second electrode comprises n second electrodes, and the third electrode comprises (n−1) third electrodes, wherein n is an integer of 3 or more.

6. The thin battery of claim 1 , wherein a porosity A of the first active material layer is 20 to 80% inclusive, and a porosity B of each of the the second active material layers is smaller than the porosity A.

7. The thin battery of claim 1 , wherein the first active material layer includes a negative electrode active material, and a binder, and

the binder is a fluorocarbon resin including a polyvinylidene fluoride unit.

8. The thin battery of claim 1 , wherein at least a part of the non-aqueous electrolyte contained in the first active material layer is in a gel state.

9. The thin battery of claim 7 , wherein an area of the first active material layer is larger than an area of each of the second active material layers.

10. A battery-mounted device comprising:

the thin battery as defined in claim 1 ; and

flexible electronic equipment to be driven by electric power supplied from the thin battery,

wherein the thin battery and the electronic equipment are integrated together to form a sheet.

11. The thin battery of claim 2 , wherein the second electrode comprises two or more second electrodes, and

the thin battery further comprises one or more third electrodes disposed between a pair of the second electrodes,

wherein each of the one or more third electrodes has a polarity identical to the polarity of the first electrode, and includes a third current collector sheet and third active material layers attached to both surfaces of the third current collector sheet, and

the content x of the non-aqueous electrolyte per unit area of the first active material layer is larger than or equal to a content z of the non-aqueous electrolyte per unit area of each of the third active material layers.

12. The thin battery of claim 11 , wherein the content z of the non-aqueous electrolyte per unit area of each of the third active material layers is larger than the content y of the non-aqueous electrolyte per unit area of each of the second active material layers.

13. The thin battery of claim 12 , wherein the second electrode comprises n second electrodes, and the third electrode comprises (n−1) third electrodes, wherein n is an integer of 3 or more.

14. The thin battery of claim 8 , wherein an area of the first active material layer is larger than an area of each of the second active material layers.