Abstract: A flat secondary battery has a laminate-type power generation element in which two or more plate-like electrodes are laminated via separators; and a pair of rectangular exterior members defined by long sides and short sides when viewed from a lamination direction of the two or more electrodes that seal the power generation element and an electrolyte solution. At least one exterior member of the pair of the rectangular exterior members comprises: an abutting part including an abutting surface that abuts against an uppermost layer electrode of the two or more electrodes; a sealing part at which the rectangular exterior members overlap each other at an outer circumferential position of the rectangular exterior members; and an extending part that extends from the abutting part to the sealing part, and the flat secondary battery satisfies 1?LA/LB?2.

Abstract: A flat type battery includes an exterior member housing an electrolytic solution and a power generating element. The power generating element contains electrodes alternating layered between electrolyte layers, and expands with use in a layering direction of the electrodes. The exterior member forms a tightly sealed space in which the power generating element is housed, and in which an extra space is formed between the exterior member and a side surface extending along the layering direction of the power generating element. The exterior member includes a volume adjustment portion allowing for an increase in the volume of the extra space by expanding in response to a pressure rise inside the tightly sealed space while the exterior member is being pressed against the surfaces intersecting the layering direction of the power generating element due to a pressure difference between the exterior and the interior.

Abstract: A flat secondary battery has a laminate-type power generation element in which two or more plate-like electrodes are laminated via each of separators; and a pair of rectangular exterior members when viewed from a lamination direction of the two or more electrodes, the rectangular exterior members sealing the laminate-type power generation element and an electrolyte solution. At least one exterior member of the pair of the rectangular exterior members comprises: an abutting part including an abutting surface that abuts against an uppermost layer electrode of the two or more electrodes; a sealing part at which the rectangular exterior members overlap each other at an outer circumferential position of the rectangular exterior members; and an extending part that extends from the abutting part to the sealing part, and the flat secondary battery satisfies: 1.03 ? L b 2 + d 2 ? 1.

Abstract: A flat type battery includes an exterior member housing an electrolytic solution and a power generating element. The power generating element contains electrodes alternating layered between electrolyte layers, and expands with use in a layering direction of the electrodes. The exterior member forms a tightly sealed space in which the power generating element is housed, and in which an extra space is formed between the exterior member and a side surface extending along the layering direction of the power generating element. The exterior member includes a volume adjustment portion allowing for an increase in the volume of the extra space by expanding in response to a pressure rise inside the tightly sealed space while the exterior member is being pressed against the surfaces intersecting the layering direction of the power generating element due to a pressure difference between the exterior and the interior.

Abstract: A flat secondary battery has a laminate-type power generation element in which two or more plate-like electrodes are laminated via each of separators; and a pair of rectangular exterior members when viewed from a lamination direction of the two or more electrodes, the rectangular exterior members sealing the laminate-type power generation element and an electrolyte solution. At least one exterior member of the pair of the rectangular exterior members comprises: an abutting part including an abutting surface that abuts against an uppermost layer electrode of the two or more electrodes; a sealing part at which the rectangular exterior members overlap each other at an outer circumferential position of the rectangular exterior members; and an extending part that extends from the abutting part to the sealing part, and the flat secondary battery satisfies: 1.03 ? L b 2 + d 2 ? 1.

Abstract: A flat secondary battery has a laminate-type power generation element in which two or more plate-like electrodes are laminated via separators; and a pair of rectangular exterior members defined by long sides and short sides when viewed from a lamination direction of the two or more electrodes that seal the power generation element and an electrolyte solution. At least one exterior member of the pair of the rectangular exterior members comprises: an abutting part including an abutting surface that abuts against an uppermost layer electrode of the two or more electrodes; a sealing part at which the rectangular exterior members overlap each other at an outer circumferential position of the rectangular exterior members; and an extending part that extends from the abutting part to the sealing part, and the flat secondary battery satisfies 1?LA/LB?2.