Abstract: An electrode assembly is accommodated in a case and has an electrode tab. A current collector is joined to the electrode tab. The electrode tab has a stacking structure of a metal foil. A burring-processed portion is formed at least in the current collector of the electrode tab and the current collector, a width of the burring-processed portion in a direction orthogonal to a stacking direction of the metal foil being narrower from the current collector toward the electrode tab along the stacking direction. A laser-welded portion at which the electrode tab and the current collector are joined to each other is formed on the electrode tab side with the electrode tab and the current collector being arranged side by side in the stacking direction.

Abstract: A battery cell includes: a case including a main body provided with an opening, and a sealing plate that seals the main body; an electrode assembly accommodated in the case and having an electrode tab; and a current collector joined to the electrode tabs. The electrode tab has a stacking structure of metal foils, and a plurality of burring-processed portions along a stacking direction of the metal foils are formed in the electrode tab. A laser-welded portion that joins the electrode tab and the current collector is formed at least in a region located between the plurality of burring-processed portions or at least in a region adjacent to the plurality of burring-processed portions.

Abstract: Provided is a technique to reduce voids between an electrode tab and a current collecting unit in a portion where the electrode tab and the current collecting unit are welded. The secondary battery manufacturing method disclosed herein is a method of manufacturing a secondary battery including an electrode body having an electrode tab and a current collecting unit electrically connected to the electrode body. This method includes: welding between the electrode tab and the current collecting unit, by sandwiching the electrode tab between a transparent material and the current collecting unit and then applying laser to penetrate the transparent material.

Abstract: A first electrode current collector is joined to a multilayer of a positive electrode core in a part including no positive electrode active material layer of the first electrode core, by ultrasonic welding in a joint area. The joint area, at which the multilayers of the first electrode core where the first electrode cores are stacked is joined to the first electrode current collector by ultrasonic welding, includes a plurality of core recesses. A core projection is formed between each adjacent pair of the plurality of core recesses of the multilayer of the first electrode core with the first electrode core flexed in a convex shape. A gap in an arc shape is formed between the adjacent pair of the layers of the first electrode core forming the core projection. The gap has a length decreasing from an apex to a bottom of the core projection.

Abstract: A positive-electrode core laminate of a portion of a positive-electrode core on which no positive-electrode active material layer is formed is bonded to a positive-electrode current collector by ultrasonic bonding. A core recess is formed in a bonding region of the positive-electrode core laminate bonded to the positive-electrode current collector by ultrasonic bonding, a region of the positive-electrode core laminate in which the core recess is formed includes a solid-state bonding layer and a central layer, the solid-state bonding layer being formed by solid-state bonding between layers of the positive-electrode core, the central layer being disposed between the solid-state bonding layers formed on both faces of the positive-electrode core, and the first average grain size of metal crystal grains constituting the solid-state bonding layer is smaller than the second average grain size of metal crystal grains constituting the central layer.

Abstract: A negative-electrode core laminate of a portion of a negative-electrode core on which no negative-electrode active material layer is formed is bonded to a negative-electrode current collector by ultrasonic bonding. A core recess is formed in a bonding region of the negative-electrode core laminate bonded to the negative-electrode current collector by ultrasonic bonding, a region of the negative-electrode core laminate in which the core recess is formed includes a solid-state bonding layer and a central layer, the solid-state bonding layer being formed by solid-state bonding between layers of the negative-electrode core, the central layer being disposed between the solid-state bonding layers formed on both faces of the negative-electrode core. The average grain size of metal crystal grains constituting the solid-state bonding layer is smaller than the average grain size of metal crystal grains constituting the central layer.

Abstract: A positive-electrode core laminate of a portion of a positive-electrode core on which no positive-electrode active material layer is formed is bonded to a positive-electrode current collector by ultrasonic bonding. A core recess is formed in a bonding region of the positive-electrode core laminate bonded to the positive-electrode current collector by ultrasonic bonding, a region of the positive-electrode core laminate in which the core recess is formed includes a solid-state bonding layer and a central layer, the solid-state bonding layer being formed by solid-state bonding between layers of the positive-electrode core, the central layer being disposed between the solid-state bonding layers formed on both faces of the positive-electrode core, and the first average grain size of metal crystal grains constituting the solid-state bonding layer is smaller than the second average grain size of metal crystal grains constituting the central layer.

Abstract: A negative-electrode core laminate of a portion of a negative-electrode core on which no negative-electrode active material layer is formed is bonded to a negative-electrode current collector by ultrasonic bonding. A core recess is formed in a bonding region of the negative-electrode core laminate bonded to the negative-electrode current collector by ultrasonic bonding, a region of the negative-electrode core laminate in which the core recess is formed includes a solid-state bonding layer and a central layer, the solid-state bonding layer being formed by solid-state bonding between layers of the negative-electrode core, the central layer being disposed between the solid-state bonding layers formed on both faces of the negative-electrode core. The average grain size of metal crystal grains constituting the solid-state bonding layer is smaller than the average grain size of metal crystal grains constituting the central layer.

Abstract: A secondary battery includes a positive electrode plate including a positive electrode core body on which a positive electrode active material layer is formed and a positive electrode current collector joined to the positive electrode core body. The layered positive electrode core body includes a joined portion joined to a positive electrode current collector. When the product of the thickness of one layer of a portion of the positive electrode core body not joined to the positive electrode current collector and the number of layers of the positive electrode core body at the joined portion is Tp1, the joined portion includes a first region having a thickness less than Tp1 and a second region having a thickness more than Tp1 in a layered direction of the positive electrode core body.

Abstract: Battery with a flexible laminate casing includes a means for fixing the electrode assembly (2) within the casing (1, 18). The fixing means may be a frame (19, 33, 38, 50, 54) attached to the periphery of the electrode assembly, or an insulating spacer (59, 69, 70, 77, 78) encased within the casing together with the electrode assembly such as to fill a space between one end of the electrode assembly and the casing. Alternatively, the fixing means may be constructed of a material with which the casing and the electrode assembly are joined together by applying heat and pressure, or may be an abutting surface (87h) provided to the casing (87) itself such as to make contact with one end face of the electrode assembly within the casing.

Abstract: The present invention relates to a construction of an explosion-proof safety vent for small-size non-aqueous electrolyte batteries such as prismatic lithium-ion secondary batteries or with an oval cross section hence with a small area of seal plate, and to a method of producing a seal plate. It aims at securing safety of a battery by allowing an explosion-proof vent to operate without fail with a simple construction at no sacrifice of the capacity. In order to fulfill this aim, it provides an explosion-proof safety vent wherein upper peripheral edge of an opening of a bottomed cell container made of metal and the periphery of a seal plate made of metal are hermetically sealed by laser welding, a rivet serving as a terminal is inserted in a through hole provided on the central portion of the seal plate and hermetically fixed by crimping via a gasket, an exhaust hole is provided between the terminal and the periphery of the seal plate, and the exhaust hole is closed by a metal foil.

Abstract: The present invention provides a sealed battery having a large capacity by using a thin safety valve device so as to increase a volume of a cell element. The sealed battery has a high safety owing to the thin safety valve device having an elastic valve element comprising an ethylene-propylene elastomer and thermoplastic resin particles dispersed in the ethylene-propylene elastomer. The elastic valve element is produced by mixing thermoplastic resin particles with an ethylene-propylene elastomer material, molding the mixture into a predetermined shape and, at the same time, crosslinking the ethylene-propylene elastomer material.