Flexible battery and flexible electronic device including the same

A flexible battery comprising:

• a cell stack comprising a plurality of unit cells, wherein each of the unit cells comprises:
• a negative electrode,
• a positive electrode,
• an electrolyte layer disposed between the negative electrode and the positive electrode, and
• a first polymer film surrounding the negative electrode, the positive electrode, or the electrolyte layer;
• and
• an external casing sealing the cell stack,
• wherein the plurality of unit cells are in sliding contact with each other, and
• wherein the cell stack has a flexibility of a curvature radius of 50 mm.

A flexible battery comprising:

• a cell stack comprising a plurality of unit cells, wherein each of the unit cells comprises:
• a negative electrode,
• a positive electrode,
• an electrolyte layer disposed between the negative electrode and the positive electrode, and
• a first polymer film surrounding the negative electrode, the positive electrode, or the electrolyte layer;
• and
• an external casing sealing the cell stack,
• wherein the plurality of unit cells are in sliding contact with each other, and
• wherein the cell stack has a capacity retention of at least 98% after 100 bending cycles over a cylinder having a diameter of 100 mm.

An electronic device comprising:

• a flexible battery having a cell stack and an external casing sealing the cell stack,
• wherein the cell stack includes a plurality of unit cells, and each of the unit cells comprises:
• a negative electrode,
• a positive electrode,
• an electrolyte layer disposed between the negative electrode and the positive electrode, and
• a first polymer film surrounding the negative electrode, the positive electrode, or the electrolyte layer;
• wherein the plurality of unit cells are in sliding contact with each other;
• and
• wherein
• the cell stack has a flexibility of greater than 2 mm when a 12 mm by 42 mm portion is deflected under a 17 g load,
• the cell stack has a flexibility of the curvature radius of 50 mm, or
• the cell stack has a capacity retention of at least 98% after 100 bending cycles over a cylinder having a diameter of 100 mm.