Abstract: A secondary battery includes a positive electrode, a negative electrode, a separator, and an electrolytic solution. The separator is disposed between the positive electrode and the negative electrode. The separator includes a porous layer and a covering layer. The covering layer is disposed between the porous layer and the positive electrode. The covering layer includes insulating particles. The insulating particles each have a major axis and a minor axis. An average aspect ratio of the insulating particles is greater than or equal to 2. The average aspect ratio is defined by the major axis and the minor axis of each of the insulating particles. The insulating particles include inclined particles. An inclination angle of each of the inclined particles is greater than or equal to 45° and less than or equal to 135°. The inclination angle is defined by a surface of the porous layer and the major axis. The positive electrode includes positive electrode active material particles.

Abstract: A secondary battery includes a positive electrode, a negative electrode, a separator, and an electrolytic solution. The separator is disposed between the positive electrode and the negative electrode. The positive electrode includes primary particles as a positive electrode active material. The separator includes a porous layer and a covering layer. The covering layer is disposed between the porous layer and the positive electrode. The covering layer includes insulating particles. The insulating particles each have a major axis and a minor axis. An average particle size of the primary particles is greater than or equal to 100 nm and less than or equal to 2120 nm. A ratio of an average length of the respective minor axes of the insulating particles to the average particle size is greater than or equal to 0.22 and less than or equal to 1.00.

Abstract: A secondary battery is provided and includes an exterior body having a first exterior portion having an accommodation portion having an accommodation space for accommodating a laminated body and a flange portion around the accommodation portion, and a second exterior portion that covers the accommodation space and to which the flange portion is joined, each of the first exterior portion and the second exterior portion has a laminated structure including a metal layer and a resin layer, a joint portion of the first exterior portion and the second exterior portion includes a first resin portion in which a resin layer of the flange portion and the resin layer of the second exterior portion are joined, a second resin portion having a projecting portion projecting from the first resin portion to the accommodation space, a sectional shape of the exterior body has a recessed portion having a bottom at a connection point between an inner surface of a resin layer of the accommodation portion and a surface of the proje

Abstract: A secondary battery includes a positive electrode, a negative electrode, and a separator. The separator is interposed between the positive electrode and the negative electrode. The separator includes a porous layer, a first adhesion layer, and a second adhesion layer. The first adhesion layer is provided between the porous layer and the positive electrode, and is adhered to the positive electrode. The second adhesion layer is provided between the porous layer and the negative electrode, and is adhered to the negative electrode. After the separator is heated at a heating temperature of 130° C.±5° C. for a heating time of one hour, an adhesion strength of the first adhesion layer with respect to the positive electrode is larger than an adhesion strength of the first adhesion layer with respect to the porous layer, and an adhesion strength of the second adhesion layer with respect to the negative electrode is larger than an adhesion strength of the second adhesion layer with respect to the porous layer.

Abstract: A secondary battery includes a positive electrode, a negative electrode, and an electrolytic solution. The positive electrode includes a positive electrode active material layer. The positive electrode active material layer includes a lithium-nickel composite oxide of a layered rock-salt type.

Abstract: A secondary battery includes a positive electrode, a negative electrode, and an electrolytic solution. The negative electrode includes a silicon-containing material and a plurality of single-walled carbon nanotubes. The single-walled carbon nanotubes have a maximum outer diameter of 5 nanometers or less.

Abstract: A battery includes a positive electrode, a negative electrode, and an electrolyte. The negative electrode includes an active material having grains and a binder having a reticulated structure. In this battery, spaces between the grains of the active material are filled with the reticulated structure of the binder.

Abstract: A battery includes a positive electrode, a negative electrode, and an electrolyte. The negative electrode includes an active material having grains and a binder having a reticulated structure. In this battery, spaces between the grains of the active material are filled with the reticulated structure of the binder.