| 主权项 |
1. A capacitor comprising:
an electrode group unit including:
a wound electrode group formed by winding a stacked member around a cylindrical axial core, the stacked member being formed by stacking an electrode having one of positive and negative polarities and formed of an elongated current collector having an active material layer formed thereon such that a first welded portion is left on one width-direction end of the electrode having the one of the polarities, a separator, and an electrode having the other of the polarities and formed of an elongated current collector having an active material layer formed thereon such that a second welded portion is left on the other width-direction end of the electrode having the other of the polarities;a first current collecting member supported by one end of the axial core and welded to the first welded portion of the electrode having the one of the polarities and included in the wound electrode group, anda second current collecting member supported by the other end of the axial core and welded to the second welded portion of the electrode having the other of the polarities and included in the wound electrode group; an electrically conductive bottomed cylindrical container having an opening portion at one end thereof and configured to contain the electrode group unit therein; and an electrically conductive lid member electrically insulated from the container and configured to block the opening portion of the container, wherein: the first current collecting member is electrically connected to the container; the second current collecting member is electrically connected to the lid member; the first current collecting member includes:
a protruded portion protruded in a direction away from the axial core and fitted with the one end of the axial core,a first welding portion located on an outer side of the protruded portion and extending outward in a radial direction of the axial core to be welded to the first welded portion of the electrode having the one of the polarities, andat least one slit extending across the protruded portion and the first welding portion and penetrating the protruded portion and the first welding portion in a thickness direction; the at least one slit includes one slit passing through a center of the protruded portion and extending entirely across the protruded portion such that both ends of the one slit reach the first welding portion; the first welding portion of the first current collecting member includes a plurality of first elongated projecting portions for welding, the plurality of first elongated projecting portions projecting toward the wound electrode group, opening toward a bottom portion of the container, and being formed at equal intervals in a circumferential direction about the protruded portion; the plurality of first elongated projecting portions are formed to extend between the protruded portion and an outer periphery of the first welding portion; two of the plurality of first elongated projecting portions are disposed on an extension line of the slit, and the two first elongated projecting portions are shorter than the rest of the plurality of first elongated projecting portions; the plurality of first elongated projecting portions are welded to the first welded portion by laser welding; a pair of recessed portions are formed at the one end of the axial core to penetrate the axial core in the radial direction of the axial core, open toward the protruded portion, and oppose each other in the radial direction; the pair of recessed portions coincide with the slit when the one end of the axial core is fitted with the protruded portion; the second current collecting member includes:
a through hole to be fitted with the other end of the axial core,a second welding portion located on an outer side of the through hole and extending outward in the radial direction of the axial core to be welded to the second welded portion of the electrode having the other of the polarities, anda tab having two ends, one of the two ends being integrally provided with the second welding portion and the other of the two ends being electrically connected to the lid member; at least one elongated projection is formed in the vicinity of the one end of the tab to extend in a width direction of the tab, projects toward the wound electrode group, and opens toward the lid member; the second welding portion of the second current collecting member includes a recessed portion extending from an outermost periphery of the second welding portion toward the through hole and penetrating the second welding portion in a thickness direction; and the one end of the tab is integrally provided with a bottom portion of the recessed portion; the second welding portion of the second current collecting member includes a plurality of second elongated projecting portions for welding, the plurality of second elongated projecting portions projecting toward the wound electrode group, opening toward the lid member, and being formed at intervals in a circumferential direction about the through hole; and the plurality of second elongated projecting portions are formed to extend between the through hole and an outer periphery of the second welding portion; the plurality of second elongated projecting portions are terminated before the outermost periphery; the through hole is defined by being surrounded by a pair of parallel edge portions and a pair of arcuate edge portions connecting both ends of the pair of parallel edge portions; and the plurality of second elongated projecting portions are welded to the second welded portion by laser welding. |
