LIQUID LEVEL DETECTION DEVICE FOR BATTERY, AND BATTERY PROVIDED WITH THE SAME

PROBLEM TO BE SOLVED: To provide a liquid level detection device of a lead battery electrolyte which has a reduced cost and an excellent precision without changing an inner structure of the lead battery to a large extent. SOLUTION: The liquid level detection device is provided with a temperature sensor arranged at a position close to a lower limit level of the electrolyte of a lead battery case outer surface and a means to memorize temperature information with the passage of time obtained by the temperature sensor. By utilizing a difference thermal capacities between the electrolyte and space and by a variation amount and variation speed of the battery temperature detected by the temperature sensor, a position of the liquid level, especially, whether or not the electrolyte liquid level is higher than the lower limit position, can be detected at a reduced cost and in a high precision without changing a battery inner structure to a large extent. COPYRIGHT: (C)2009,JPO&INPIT