All solid secondary battery and method of manufacturing the same

1. A solid state battery comprising:

a negative electrode layer comprising a negative electrode active material;

a positive electrode layer comprising a positive electrode active material;

a solid electrolyte layer disposed between the negative electrode layer and the positive electrode layer;

a negative electrode current collector; and

a positive electrode current collector,

wherein the solid electrolyte layer contacts the negative electrode layer and the positive electrode layer,

wherein a major surface area of each of the negative electrode current collector layer, the negative electrode layer, the solid electrolyte layer, the positive electrode layer, and the positive electrode current collector are the same, or the major surface area of each of the positive electrode layer and the positive electrode current collector layer are smaller than the major surface area of each of the negative electrode current collector layer, the negative electrode layer, and the solid electrolyte layer, and

wherein the solid state battery satisfies Equation 1:

{( V p −V 980 )/ V p ×100%}≦3%  Equation 1

wherein

V p is a total volume of the negative electrode layer, the positive electrode layer, and the solid electrolyte layer, and

V 980 is a total volume of the negative electrode layer, the positive electrode layer, and the solid electrolyte layer under a total pressure of about 980 megapascals.

2. The solid state battery of claim 1 , wherein the pressure is a hydrostatic pressure.

3. The solid state battery of claim 1 , wherein V p in Equation 1 is determined at a pressure of about 450 megapascals or greater.

4. The solid state battery of claim 1 , wherein the negative electrode layer, the positive electrode layer, and the solid electrolyte layer are each a consolidated powder.

5. The solid state battery of claim 1 , wherein the negative electrode layer, the positive electrode layer, and the solid electrolyte layer each comprise consolidated particles.

6. The solid state battery of claim 1 , wherein the solid electrolyte layer comprises a sulfide solid electrolyte comprising lithium, phosphorous, and sulfur.

7. The solid state battery of claim 1 , wherein the solid electrolyte comprises Li 2 S—P 2 S 5 .

8. The solid state battery of claim 1 , wherein a pressure applied to the negative electrode layer, the positive electrode layer, and the solid electrolyte layer is a pressure of one atmosphere or less.

9. The solid state battery of claim 1 , wherein a discharge capacity at a 50 th cycle of the solid state battery is about 95% or greater than a discharge capacity at a first cycle of the solid state battery, when charged and discharged at about 25° C. and at a current density of about 0.5 milliamperes per square centimeter in a voltage range of about 4 volts to about 2.5 volts.

10. The solid state battery of claim 1 , wherein a cell resistance of the solid state battery after charging at the fifth cycle is about 40 ohms or less, when charged and discharged at about 25° C. and at a current density of about 0.5 milliamperes per square centimeter in a voltage range of about 4 volts to about 2.5 volts.

11. The solid state battery of claim 1 ,

wherein the solid state battery satisfies Equation 1

{( V p −V 980 )/ V p ×100%}≦3%, and  Equation 1

wherein an initial discharge capacity of the solid state battery is about 95% or greater of an initial discharge capacity of a solid state battery satisfying the equation {(V p −V 980 )/V p ×100}=0%,

wherein charging and discharging are performed at about 25° C. and at a current density of about 0.5 milliamperes per square centimeter in a voltage range of about 4 volts to about 2.5 volts.

12. The solid state battery of claim 1 , wherein the major surface area of the positive electrode layer is smaller than the major surface area of each of the negative electrode layer and the solid electrolyte layer.

13. The solid state battery of claim 12 , wherein the positive electrode layer, the negative electrode layer, and the solid electrolyte layer are each product of press consolidation.

14. The solid state battery of claim 1 , wherein the solid state battery is an all solid state battery.

15. The solid state battery of claim 1 , wherein the solid state battery is an alkali ion secondary battery.

16. A method of manufacturing a solid state battery, the method comprising:

providing a positive electrode current collector disposed on a positive electrode layer;

providing a negative electrode current collector disposed on a negative electrode layer;

disposing a solid electrolyte layer between the negative electrode layer and the positive electrode layer to provide a laminate, wherein a major surface area of each of the negative electrode current collector layer, the negative electrode layer, the solid electrolyte layer, the positive electrode layer, and the positive electrode current collector are the same, or the major surface area of each of the positive electrode layer and the positive electrode current collector layer are smaller than the major surface area of each of the negative electrode current collector layer, the negative electrode layer, and the solid electrolyte layer; and

pressing the laminate to consolidate the laminate, wherein the product of the pressing satisfies Equation 1:

{( V p −V 980 )/ V p ×100%}≦3%  Equation 1

wherein

V p is the total volume of the negative electrode layer, the positive electrode layer, and the solid electrolyte layer after consolidation, and

V 980 is a total volume the negative electrode layer, the positive electrode layer, and the solid electrolyte layer when a pressure of 980 megapascals is applied.

17. The method of manufacturing the solid state battery of claim 16 , wherein the pressure is a hydrostatic pressure.

18. The method of manufacturing the solid state battery of claim 16 , wherein the pressing the laminate comprises applying a hydrostatic pressure to the laminate,

wherein the laminate is formed on a support comprising a rigid plate, which is configured to apply a first hydrostatic pressure to a portion of the laminate that contacts the support and second hydrostatic pressure to a portion of the laminate that does not contact the support, and

wherein the first hydrostatic pressure and the second hydrostatic pressure are different.

19. The method of manufacturing the solid state battery of claim 16 , wherein in the pressing the laminate, the hydrostatic pressure applied to the portion of the laminate that does not contact the support is about 450 megapascals or greater.

20. The method of manufacturing the solid state battery of claim 16 , wherein the pressure is applied by a press.