A safety device for preventing overcharge of secondary batteries and secondary batteries therewith

• Main Authors: HA, SOO-HYUN, CHANG, SUNG-KYUN, LEE, JAE-HYUN, CHO, JEONG-JU, LEE, JOON-HWAN
• Format: Patent
• Language: English
• Published: 21.10.2007
• Subjects: BASIC ELECTRIC ELEMENTS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTINGELECTRIC POWER; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRICITY; GENERATION; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY; SYSTEMS FOR STORING ELECTRIC ENERGY

An object of the present invention is to provide the device for protecting a secondary battery safely from over voltage and overheating caused by the overcharge by using simple safety device, which provides a contacted safety device which connects between a constant voltage element showing a discharge characteristic in the state of over voltage and a MIT (metal insulator transition) element showing a discharge characteristic in the state of overheating. Each of the constant voltage element and the MIT element are connected in parallel between a cathode lead and an anode lead of the secondary battery. The contacted safety device has a characteristic combining a discharge/heat dissipation characteristic of the constant voltage element and a discharge characteristic of the MIT element which immediately responds to the heat dissipation of the constant voltage element, resulting in effect of preventing overcharge advantageously since the contacted safety device makes discharge in terms of 2 factors of voltage and temperature in case of overcharge.