Thermal Runaway Protection System for a Battery Charger

• US 20090218990A1
• Filed: 02/29/2008
• Published: 09/03/2009
• Est. Priority Date: 02/29/2008
• Status: Active Grant

• Current Assignee: Schumacher Electric Corporation
• Original Assignee: Schumacher Electric Corporation
• Inventors: Johnson, Thomas F., Whiting, John S.
• Granted Patent: US 7,834,593 B2
• Time in Patent Office: Days
• US Class Current: 320/137
• CPC Class Codes: H01M 10/443 in response to temperature
• CPC Class Codes: H01M 10/486 for measuring temperature
• CPC Class Codes: H02J 7/00309 Overheat or overtemperature protection
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A protection system and method for a battery charger is disclosed for detecting a thermal runaway condition in a battery during charging in order to protect the battery when such a thermal runaway condition has been detected. The protection system in accordance with the present invention does not require external temperature sensors nor does it rely on actions by the technician or user. Briefly, the protection system includes one or more electrical sensors normally provided with conventional battery chargers for sensing one or more electrical parameters during charging and providing an indication of a possible thermal runaway condition based upon the trend of the electrical charging parameters. In general, the protection system monitors the charging characteristics of a battery for a complete or partial charging cycle. If the charging characteristics deviate from a normal or otherwise indicate an anomaly, as determined by software, the system assumes there may be a thermal runaway condition and executes a protection measure, such as terminating charging of the battery. Even though the anomaly may not be the result of a thermal runaway condition, the protection system in accordance with the present invention treats the anomaly as an indication of a thermal runaway condition even though some other problem is the reason for the anomaly. For example, when the anomaly is the result of a bad cell, battery charging is terminated to prevent a thermal runaway condition and not because a thermal runaway condition is detected.

Claims

1. A method for detecting a thermal runaway condition comprising:

monitoring one or more charging parameters available at a battery charger during the charging of a battery; and

providing an indication of a thermal runaway condition as a function of said one or more parameters.