Abstract: A lithium ion secondary battery that, when current collector tabs of the lithium ion secondary battery are bundled together and joined with a lead terminal, can prevent the current collector tabs from cracking or breaking and can ensure that both of an electrical connection and a physical connection between the current collector tabs and the lead terminal are guaranteed is provided.

Abstract: To provide a lithium ion secondary battery in which it is possible to prevent an electrode end part from cracking, when current collector tabs of the lithium ion secondary battery are bound to each other and joined to a lead terminal. A lithium ion secondary battery includes a lithium ion secondary battery main body and a lead terminal. The lithium ion secondary battery main body has a laminated body repeatedly disposed with positive electrodes respectively including positive electrode current collectors, solid electrolytes, and negative electrodes respectively including negative electrode current collectors. The current collectors respectively extend from an end face of the laminated body in an identical direction to constitute a plurality of current collector tabs. The lead terminal is electrically coupled to the plurality of current collector tabs. The current collector tabs and the lead terminal are coupled to each other via an electrically-conductive tab guiding part.

Abstract: A conventional secondary battery has a problem that an internal resistance is very high in a low SOC region and necessary output cannot be taken out. In a secondary battery including a positive electrode and a negative electrode, a capacity difference from a terminal potential of a positive electrode discharge curve to a terminal voltage of a battery discharge curve of the secondary battery with respect to a discharge capacity of the secondary battery is 14% to 26%.

Abstract: An object of this present invention is to provide: a lithium-ion secondary battery 1 constructed to easily interpose an electrical insulating protection film 41 between a battery container 2 and an electricity-generating element 3, to facilitate automatic mounting of the insulating protection film 41, and thus to be highly producible; and a method of manufacturing the battery. The lithium-ion secondary battery 1 of the invention is characterized in that the battery is electrically insulated between the battery container 2 and the electricity-generating element 3, and in that the insulating protection film 41 of a sheet-like form is wrapped around the electricity-generating element 3.

Abstract: An object of the present invention is to provide a flat-winding type secondary battery having a simple structure and thus capable of being manufactured in a simplified manufacturing process. A flat-winding type secondary battery according to the present invention is a flat-winding type secondary battery having a flat-shaped winding group obtained by winding positive and negative electrodes with separators interposed therebetween. The winding group has a shaft core having a configuration in which leading end portions of a sheet member at both sides in a winding direction are folded in an a mutually approaching direction and disposed at positions separated from each other, the sheet member having a higher bending rigidity than that of any of the positive and negative electrodes and separators.

Abstract: A flat wound secondary battery and a method for producing the same provides for the suppression of wrinkles formed on an electrode by irregularities on a welded portion. A secondary battery has a wound electrode body including a positive electrode and a negative electrode that are wound flat around a shaft core with a separator interposed between the electrodes, and a battery container that contains the wound electrode body. The shaft core includes a wound resin sheet having higher flexural rigidity than the positive electrode, the negative electrode, and the separator. The shaft core includes an innermost portion that forms the innermost periphery of the shaft core and an extended portion to a winding terminal end from the innermost portion. The separator includes a bonded portion to the extended portion and a separator winding portion that winds only the separator at least one turn around the shaft core.

Abstract: A shaft core includes a positive electrode shaft core portion having a positive electrode splaying portion at one end, a negative electrode shaft core portion having a negative electrode splaying portion at the other end, and an insulation portion that mutually insulates and integrates the positive and negative electrode shaft core portions. The positive electrode plate is electrically connected to the positive electrode collector in a state of being splayed through the positive electrode splaying portion, and the negative electrode plate is electrically connected to the negative electrode collector being splayed through the negative electrode splaying portion.

Abstract: An object of this present invention is to provide: a lithium-ion secondary battery 1 constructed to easily interpose an electrical insulating protection film 41 between a battery container 2 and an electricity-generating element 3, to facilitate automatic mounting of the insulating protection film 41, and thus to be highly producible; and a method of manufacturing the battery. The lithium-ion secondary battery 1 of the invention is characterized in that the battery is electrically insulated between the battery container 2 and the electricity-generating element 3, and in that the insulating protection film 41 of a sheet-like form is wrapped around the electricity-generating element 3.

Abstract: A secondary battery includes a vessel exterior provided with positive and negative electrode external terminals; an electrode group in which positive and negative electrode plates are wound while allowing a separator to intervene therebetween, and collector portions are provided at the both ends thereof; a shaft core in which the positive and negative electrode plates are wound and which has positive and negative electrode shaft core portions at both ends thereof, the positive and negative electrode shaft core portions being insulated from each other by an insulation portion; and positive and negative electrode collectors which are supported by the vessel exterior and constitute a current path reaching the positive and negative electrode external terminals from the electrode group, the positive and negative electrode shaft core portions being joined with collecting portion of the positive and negative electrode plates and also welded to the positive and negative electrode collectors, respectively.

Abstract: A shaft core includes a positive electrode shaft core portion having a positive electrode splaying portion at one end, a negative electrode shaft core portion having a negative electrode splaying portion at the other end, and an insulation portion that mutually insulates and integrates the positive and negative electrode shaft core portions. The positive electrode plate is electrically connected to the positive electrode collector in a state of being splayed through the positive electrode splaying portion, and the negative electrode plate is electrically connected to the negative electrode collector being splayed through the negative electrode splaying portion.

Abstract: A lithium-ion secondary cell includes a winding electrode assembly. The exposed area of the positive-electrode metal current collector body is formed at one end in a winding axis direction of the winding electrode assembly, and the exposed area of the negative-electrode metal current collector body is formed at another end in the winding axis direction of the winding electrode assembly; and the negative-electrode metal current collector body is a copper foil rolled to a thickness between 6 ?m and 15 ?m in which one or more of additive elements of Zr, Ag, Au, Pt, Cr, Cd, Sn, Sb, and Bi are added to Cu having a purity of equal to or greater than 99.9%, and the negative-electrode active material mix layer has a cavity volume ratio of between 30% and 60%.