Patent ID: 6859015

Claim:
A control unit for controlling the charging process of a battery, comprising: (a) a charger circuit coupled to the battery; (b) a circuit for prohibiting said charging process when at least the following conditions recited in paragraphs (i) and (ii) below are both met: (i) T B >T max , where T B designates the actual temperature of the battery and T max designates the highest permissible battery temperature, and (ii) in addition to the condition of paragraph (i) above being met, at least one of the following three conditions of paragraph I, II or III are met; (I) if the battery voltage U B lies below a predetermined threshold value U o (II) if the charging current I ch exceeds a predetermined maximum value I max , or (III) an end-of-charge condition, wherein said end-of-charge condition is generated when a change in either the battery current or voltage, dI or dU, respectively, decreases within a predetermined time period below a respective predetermined threshold level; said prohibiting circuit comprising respective conditional and final prohibition circuits, wherein said final prohibition circuit is triggered by the following two of said conditions, namely, the battery voltage U B lies below a predetermined threshold value U o and the charging current I ch exceeds a predetermined maximum value I max ; said conditional prohibition circuit being triggered by any one of said prohibition conditions, said central control circuit further comprising a restart circuit for restarting a conditionally prohibited charging process, said restart circuit comprising a plurality of inputs through which respective restart signals can be received, said restart circuit being responsive to said restart signals to trigger restart of operation of said charger circuit in response to the temperature of the battery (T B ) being lower than an acceptable predetermined temperature (T ok ), said restart signals controlling control unit operations for the same respective parameters as those constituting said conditional prohibitions, actual trigger values of the restart condition being separated from trigger values associated with conditional prohibition parameters to define a hysteresis characteristic.