Abstract: A secondary battery includes an outer package member, a battery device, an electrode terminal, and an insulating member. The outer package member has a through hole. The battery device is contained inside the outer package member. The electrode terminal is disposed on an outer side of the outer package member and covers the through hole. The insulating member is disposed between the electrode terminal and the outer package member, and does not cover the through hole. The outer package member includes a container part having an opening and containing the battery device inside, and a cover part having the through hole and closing the opening. The container part and the cover part are joined to each other. The insulating member has a temperature of deflection under load ranging from 60° C. to 150° C. both inclusive. The cover part has a thickness smaller than a thickness of the container part.

Abstract: A power supply apparatus includes a primary battery, a secondary battery, and an output terminal. The secondary battery is coupled in parallel with the primary battery. The output terminal outputs electric power from the secondary battery to an outside. A discharge capacity of the primary battery is larger than a discharge capacity of the secondary battery.

Abstract: A battery includes an outer package member, a battery device, a sealing member, and a terminal member. The outer package member has an outer diameter and a height. The battery device is contained inside the outer package member. The sealing member has an insulating property. The terminal member is supported by the outer package member via the sealing member. A ratio of the outer diameter to the height is greater than or equal to 0.1 and less than 1. The outer package member includes a container member and a cover member. The container member has an opening, and contains the battery device in an inside of the container member. The cover member is welded to the container member, closes the opening, and has a through hole. The terminal member is fixed to the cover member via the sealing member, and covers the through hole. A fixation strength of the terminal member to the cover member is lower than a welding strength of the cover member to the container member.

Abstract: A secondary battery includes an outer package member, an electrode terminal, and a battery device. The outer package member has a flat and columnar shape and includes a first bottom part and a second bottom part opposed to each other. The electrode terminal is supported by the first bottom part and is insulated from the first bottom part. The battery device is contained inside the outer package member and includes a first electrode and a second electrode. The first bottom part has a recess around the electrode terminal.

Abstract: A battery is provided. The battery includes an electrode having a flat shape. The electrode is wound and includes a through hole. The through hole is further provided in a wound-back portion of the electrode.

Abstract: A secondary battery includes a power generation element including a plurality of electrodes. The electrodes are stacked on each other in a stacking direction with a separator interposed therebetween. Each of the electrodes includes a current collector led out in a first direction intersecting the stacking direction. Each of a plurality of current collectors led out in the first direction includes an end part, and the end part includes a first bent part that is bent in a second direction intersecting the first direction. Each of a plurality of first bent parts overlaps and is in contact with an adjacent first bent part in the second direction. At least one of the first bent parts terminates at a middle point on an end face along the second direction of the power generation element.

Abstract: A secondary battery includes a negative electrode, a positive electrode, and an electrolytic solution. The negative electrode includes a negative electrode active material layer. The positive electrode includes a positive electrode active material layer. The positive electrode active material layer has a same dimension as a dimension of the negative electrode active material layer in a width direction. The positive electrode active material layer includes a reaction active part in which charging and discharging reactions proceed, and a reaction less-active part in which the charging and discharging reactions proceed less easily than in the reaction active part. The reaction less-active part includes one end part, another end part, or both of the positive electrode active material layer in the width direction.

Abstract: A secondary battery includes a positive electrode, a negative electrode, and an electrolytic solution. The positive electrode includes a lithium-cobalt composite oxide having a layered rock-salt crystal structure. The negative electrode includes graphite. An open circuit potential of the negative electrode measured in a full charge state is from 19 mV to 86 mV. A potential variation of the negative electrode is greater than or equal to 1 mV when the secondary battery is discharged from the full charge state by a capacity corresponding to 1% of a maximum discharge capacity. The maximum discharge capacity is obtained when the secondary battery is discharged with a constant current from the full charge state until the closed circuit voltage reaches 3.00 V, following which the secondary battery is discharged with a constant voltage of the closed circuit voltage of 3.00 V for 24 hours.

Abstract: A separator includes a substrate layer that is porous, and a surface layer that is provided on at least one main face of the substrate layer and that has an uneven shape. The surface layer includes first particles that are for forming convexities of the uneven shape and that are a main component of the convexities, second particles that have a smaller average particle size than the first particles, cover at least a part of a surface of the first particles, and cover at least a part of a surface of the substrate layer that is exposed between the first particles, and a resin material.

Abstract: A separator includes a substrate layer and a porous surface layer that is provided on at least one major surface of the substrate layer and contains a first particle, a second particle, and a resin material. The surface layer includes a first region configured by the first particle and a second region configured by the second particle and the resin material.

Abstract: A separator has: a substrate including a porous film; and a surface layer which is provided on at least one surface of the substrate, which includes a vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer, and which has a plurality of minute pores.

Abstract: A battery is provided. The battery includes an electrode having a flat shape. The electrode is wound and includes a through hole. The through hole is further provided in a wound-back portion of the electrode.