TECHNICAL FIELD

The present invention relates to a battery including a winding-type electrode group, particularly to a winding-type battery including a battery case having a small outer diameter.

BACKGROUND ART

Recently, the performance of portable devices has been remarkably increasing. It is desired that power sources of such portable devices are small and have a high capacity. While, the manufacturing of high-capacity batteries becomes difficult as the sizes of the batteries become small.

Patent Literature 1 discloses a battery that includes a small cylindrical metal can, a winding-type electrode group accommodated in the metal can, and a sealing member for sealing an opening in the metal can. In order to suppress an internal short circuit, a ring-shaped insulating member is disposed between an end surface of the electrode group and the sealing member. For the same purpose, in Patent Literature 2, a plate-shaped insulating ring is covered on the end surface of the electrode group.

CITATION LIST

Patent Literature

PTL 1: Unexamined Japanese Patent Publication No. 2014-222670

PTL 2: Unexamined Japanese Patent Publication No. 2000-48802

SUMMARY OF THE INVENTION

In Patent Literatures 1 and 2, an independent insulating member is disposed between an electrode group and a sealing member. An operation of disposing such an insulating member in a battery case requires carefulness as the battery becomes small. For example, when the insulating member has been obliquely inserted into the battery case, the insulating member can be damaged during processing of the proximity of an opening in the battery case. During the processing, a load is charged also on an end surface of the electrode group, and the electrode group can be damaged. When the size or processing accuracy of the insulating member varies, an operation of inserting the insulating member into the battery case becomes more difficult. When the battery is vibrated during the use of the battery, it is feared that the insulating member collides against the electrode group to damage the electrode group.

In view of the above-mentioned problems, a winding-type battery of one aspect of the present disclosure includes: a battery case having an opening; a power generating element accommodated in the battery case; a cap for blocking the opening in the battery case; and a gasket for insulating the battery case from the cap. The power generating element includes a first electrode, a second electrode having a polarity different from that of the first electrode, a separator interposed between the first electrode and the second electrode, and an electrolyte. The first electrode and the second electrode are wound via the separator to form an electrode group, and the first electrode is connected to the cap via a first current collecting lead, and the second electrode is connected to the battery case via a second current collecting lead. Near the end forming the opening in the battery case, an annular groove is formed so as to reduce the diameter of the battery case. The gasket includes: an annular seal portion interposed between a rim of the cap and the region from the groove of the battery case to the end thereof, and a tubular portion that is integrated with the seal portion, and is disposed coaxially with the seal portion and disposed closer to the electrode group than the seal portion is. The first current collecting lead is connected to the cap through a hollow in the tubular portion.

The present disclosure can simplify the manufacturing process of a winding-type battery and reduce the cost of the manufacturing process, can reduce the defective fraction during manufacturing the battery, and can increase the vibration resistance of the battery.

