Patent ID: 7436151
Filing Date: 2008-10-14
Classification: H02J

Abstract:
1. A method of detecting charge switching element failure in a battery system, comprising: monitoring for the presence of a battery charging current flowing to one or more battery cells of said battery system; monitoring voltage of said one or more battery cells of said battery system; using a combination of said monitored voltage and said monitored battery charging current to sense failure of said charge switching element and without disabling the battery system due to a false charging current indication; and taking one or more failure state actions only if both of the following conditions are detected to exist at the same time when said charge switching element of said battery system is supposed to be in a state that prevents flow of battery charging current to said one or more, battery cells of said battery system and not taking said one or more failure state actions if both of the following conditions are not detected to exist at the same time when said charge switching element of said battery system is supposed to be in a state that prevents flow of battery charging current to said one or more battery cells of said battery system: wherein said charge switching element forms a part of a charge circuit that is controllable to allow or disallow charging current to said one or more battery cells from said battery charging apparatus; and wherein said method further comprises controlling said charge switching element to allow or disallow charging current to said one or more battery cells.