Terminal structure for secondary battery and secondary battery

摘要

A secondary battery in which the contact resistance is not increased even if the number of housed electrodes is increased is provided. Two screw holes 11d are formed in an opposed surface 11c of a terminal body portion 11b of a positive terminal 11 that faces the stacking direction. A projecting surface 11e is provided between the two screw holes 11d to project toward a positive pressing member 25 with respect to portions provided with the screw holes 11d. The projecting surface 11e projects toward the positive pressing member 25 by 0.2 mm with respect to the portions provided with the two screw holes 11d.

主权项

1. A terminal structure for a secondary battery including an electrode group including a plurality of electrodes each having a tab and stacked via a separator, the terminal structure comprising:
a terminal including a terminal portion and a terminal body portion; and at least one pressing member attached to the terminal body portion using two or more fasteners each including a bolt and a nut, and configured to hold a stacked current collecting plate group in a sandwiched manner between the pressing member and the terminal body portion, the stacked current collecting plate group being formed by stacking a plurality of current collecting plates to which the tabs of the electrodes of the same polarity are welded, wherein: the two or more fasteners are provided such that the bolts extend in a stacking direction of the current collecting plates in the stacked current collecting plate group and one or more of the fasteners are located in each of two attachment regions spaced apart at a predetermined interval; the terminal body portion has at least one opposed surface that faces the pressing member; the pressing member has an opposed surface that faces the terminal body portion; and at least one of the opposed surface of the terminal body portion and the opposed surface of the pressing member has a projecting surface to project toward the other of the opposed surfaces of the terminal body portion and the pressing member in a region located between the two attachment regions. a terminal including a terminal portion and a terminal body portion; the projecting surface is provided on one of the opposed surfaces of the terminal body portion and the pressing member; a projecting length of the projecting surface from a non-projecting surface of the one of the opposed surfaces of the terminal body portion and the pressing member is 0.1 mm to 0.5 mm; the projecting surface has an area that is 60% to 80% of an area of the opposed surfaces of the terminal body portion and the pressing member; the projecting surface is a continuous surface; the plurality of current collecting plates are each formed with through holes through which the bolts pass; the at least one opposed surface of the terminal body portion comprises two opposed surfaces of the terminal body portion that are opposite to each other in the stacking direction; the at least one pressing member comprises two pressing members respectively provided to face the two opposed surfaces of the terminal body portion; a predetermined number of the plurality of tabs of the plurality of electrodes of the same polarity in the electrode group are welded to each of the plurality of current collecting plates, and the plurality of current collecting plates are divided into two groups and stacked to constitute two stacked current collecting plate groups; one of the stacked current collecting plate groups is held in a sandwiched manner between one of the opposed surfaces of the terminal body portion and one of the pressing members, and the remaining one of the stacked current collecting plate groups is held in a sandwiched manner between the remaining one of the opposed surfaces of the terminal body portion and the remaining one of the pressing members; the terminal body portion is formed with a plurality of through holes that each open in the two surfaces of the terminal body portion; the two pressing members are each formed with a plurality of through holes aligned with the plurality of through holes formed in the terminal body portion; the bolts having threaded portions at both ends are disposed to pass through the through holes formed in the terminal body portion and the through holes formed in the pressing members; and the nuts are screwed with both ends of the bolts; the at least one pressing member is formed from aluminum, titanium, iron, nickel, copper, zinc, silver, cadmium, or tin, and have a thickness of 5 mm to 7 mm in the stacking direction; and the at least one pressing member, the stacked current collecting plate groups, and the terminal portion are welded to each other.