| 摘要 |
PURPOSE:To make it possible to easily judge a serious problem in a circuit such as short circuit by arranging a sensor which irreversibly changes color by heat in a position visible from the outside of a battery. CONSTITUTION:When a circuit is normal, the internal resistance of a battery 1 is low and a resistance element with positive temperature coefficient (PTC element) shows room temperature resistance, and the battery 1 and the PTC element show almost no heat generation. On the other hand, when short-circuit arised, excess current flows in the circuit and the battery and the PTC element are heated by Joule heat and these temperature is increased. The ressitance of the PTC element is sharply increased by PTC characteristic and the excess current in the circuit is stopped to protect the circuit, and the color of a sensor 3 arranged on the surface of the battery 1 is irreversibly changed. When the current is stopped by the consumption of the battery or the elimination of short-circuit, the PTC element is recovered to the original state and its temperature is returned to the room temperature. However, the color of the sensor stays changed and is visible from the outside of the battery. |
