O2 Micro, Incorporated

Weidong Xue

Yan Li

Anquan Xiao

Guoxing Li

Xiaojun Zeng

Yingguo Zhang

Xiaohu Tang

Xiaofei Gong

An open cell detection system includes a battery management system. The battery management system includes a control unit that transmits an open cell detection signal, to enable a balance unit for a first time period and to disable it for a second time period, and to enable an under-voltage comparison unit and an over-voltage comparison unit for a third time period. The under-voltage comparison unit compares a voltage with a first open cell threshold and outputs a first comparison result in the third time period. The over-voltage comparison unit compares a voltage with a second open cell threshold and outputs a second comparison result in the third time period. A judging unit determines whether a connection between a first battery unit and the battery management system is inoperative based on the first and second comparison results.

Determining a status of connection between a battery unit and a battery management system

An open cell detection method includes: (a) generating a control signal by a control unit, to turn on a first balance switch for a first time period; (b) generating the control signal with the control unit, to turn off the first balance switch for a second time period; (c) measuring a voltage value on a first capacitor, with a measure unit; (d) if the voltage value on the first capacitor is less than an open cell threshold, then determining with the control unit that the first cell has an open cell failure; (e) for each cell of the cells, repeating steps (a)-(d); and (f) if at least one cell of the cells has an open cell failure, then determining with the control unit that the battery management system has an open cell failure.

Open cell detection method and open cell recovery detection method in a battery management system

Battery management systems and methods, and open cell detection systems

Open cell detection systems and methods

A battery module includes: a battery pack including multiple cells; control circuits corresponding to the cells, each control circuit including a control unit for managing the corresponding cell and a compensation unit for generating a corresponding compensation current such that the sum of the corresponding consumed current and the corresponding compensation current is equal to a target total current, where the control circuits include a first control circuit and a second control circuit, where the first control circuit includes a first control unit operating with a first consumed current, the second control circuit includes a second control unit operating with a second consumed current, and where the first control circuit conditionally generates a first compensation current and the second control circuit conditionally generates a second compensation current based on a comparison of the first consumed current and the second consumed current.

Systems and methods for compensating current in a battery module

A battery management system includes detecting circuitry and control circuitry coupled to the detecting circuitry. The detecting circuitry detects cell voltages of battery cells of a battery pack. The control circuitry alternates between a normal state and a charging prohibition state. In the normal state, charging of the battery cells is enabled and the cell voltages increase, and if a voltage of a battery cell of the battery cells exceeds a predetermined overcharge threshold, then the control circuitry transitions to the charging prohibition state. In the charging prohibition state, charging of the battery cells is disabled, and the voltage of the battery cell decreases if at least one cell of the battery cells has a voltage less than a balance threshold. If the voltage of the battery cell falls to a predetermined overcharge-released threshold, then the control circuitry transitions to the normal state and enables charging of the battery cells.

Battery management system

System and methods for current balancing

A circuit for detecting an input voltage includes a voltage-to-current converter and a current comparator. The voltage-to-current converter is operable for generating a monitoring current that varies in accordance with the input voltage. The current comparator coupled to the voltage-to-current converter is operable for comparing the monitoring current to a threshold current proportional to the temperature of the circuit, and for generating a detection signal indicating a condition of the input voltage based on a result of the comparison.

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Shanghai, China

Weidong Xue