Abstract: An apparatus for inhibiting thermal runaway of a battery cell uses a temperature sensor to measure a temperature of the cell and a discharge circuit, electrically coupled in series across terminals of the cell, to discharge the cell when its temperature exceeds a maximum normal operating temperature. The discharge circuit includes a switch and a resistive load. The apparatus may be part of a larger system that uses a processor to implement a method to discharge the cell to varying degrees in response to the degree of overheating the cell experiences.

Abstract: Disclosed herein is a battery thermal management system for maintaining the temperature of a battery pack in a hybrid vehicle below a maximum operating temperature threshold. The system comprises a battery pack having a plurality of electronically linked cells and a supply air diffuser having a pattern of openings therein for diffusing exhausted air at a substantially uniform flow throughout the battery pack. The system further comprises sensors for monitoring the temperature of at least a portion of the cells, a fan comprising an inlet through which air is drawn in and an outlet in communication with at least the supply air diffuser, for exhausting air into the first diffuser to lower the temperature of the battery pack, and an electronic control unit in communication with the sensors and the fan for controlling operation of the fan based on temperature signals received from the sensors to maintain the temperature of the battery pack below a maximum operating temperature.

Abstract: Disclosed herein is a battery management system for lithium ion batteries capable of determining a battery pack's state of capacity; determining a battery pack's state of charge limits; adjusting for voltage drops and power losses over a battery's internal and/or connector impedances; adjusting the upper and lower voltage limits of a battery pack; and of actively balancing the cells making up the battery pack. In order to achieve this functionality, the battery pack management system includes an electronic control unit, which unit is coupled to module and cell-level circuitry that is designed to measure operating conditions of the battery such as voltage and current at any given time.

Abstract: In a secondary battery charging system and charging apparatus, when using either a step-down method or a constant-current/constant-voltage method of charging a secondary battery, a switching regulator is used to vary the charging current supplied to a secondary battery in accordance with the duty cycle of one pulse, so that a voltage that exceeds a pre-established voltage value is not applied to the secondary battery.

Abstract: A high-speed secondary cell charging system is provided which accurately measures the amount of time to achieve a full-charge condition in a secondary cell. In this system, when charging a secondary cell while detecting a charging characteristic of the secondary cell, charging is performed of the secondary cell using a prescribed amount of charging current. Then, when a prescribed condition with regard to the secondary cell is detected, the secondary cell is charged once again, this time with a current that is smaller than the previous charging current. When a condition indicating the completion of the charging of the secondary cell is detected, the charging is stopped. If this condition is not detected, a yet smaller charging current is set and the charging of the secondary cell is performed once again, the above operations being repeated until a condition which indicates that the charging of the secondary cell is complete is detected.

Abstract: A conditioning and charging circuit for NiCd battries includes a switch for initially connecting the battery to a discharge resistor to discharge the battery. The battery voltage is monitored during the discharge. When the battery voltage falls to predetermined value, a timer is triggered and the switch is actuated to connect the battery to a charger. The charger charges the battery until the timer times out after a predetermined period, at which point charging is terminated. The predetermined period may be fixed, or it may be a function of ambient temperature. Thus, the battery is first discharged to a predetermined voltage and then charged for a predetermined period of time.