1. Field of the Invention
This invention relates to a battery charger for charging both AA (double A) and AAA (triple A) type batteries.
2. Description of the Related Art
Battery chargers that charge both AA and AAA type batteries, while detecting battery temperature, have been developed. The reason for detecting battery temperature during charging is because charging a battery with an abnormally high temperature results in degraded battery performance. Battery temperature rises during charging. In particular, battery temperature rises abruptly as the battery approaches full charge. Abnormal rise in battery temperature is a cause of battery characteristic degradation. To prevent battery performance degradation, battery chargers have been developed which are provided with temperature sensors to detect battery temperature (See Japanese Laid-Open Patent Publication No. 2002-199609A and HEI 5-30669A (1993)).
In the battery charger disclosed in Japanese Laid-Open Patent Publication No. 2002-199609A, a temperature sensor is inserted in soft tubing and placed in contact with a battery pack surface. This temperature sensor contacts a battery surface via the soft tubing and detects battery temperature. In the battery charger disclosed in Japanese Laid-Open Patent Publication No. HEI 5-30669A (1993), the temperature sensor is pushed out by a coil spring to thermally join with a heat conducting part. This temperature sensor detects battery temperature via the heat conducting part.