A device for monitoring battery cells of a battery string under load condition. The device has differential voltage units for each battery cell, wherein a band-pass filter is arranged downstream of each differential voltage unit, wherein the band-pass filters are connected to rectifier circuits with a smoothing circuit arranged downstream, and wherein the device is designed so the output signals of the smoothing circuits are supplied to an evaluation unit and are compared for deviations in relation to a standardized output signal.

The present invention relates to a method for determining a state of charge of a battery, including: (a) acquiring a state of charge of the battery at a current sampling time point tn; (b) acquiring a voltage Vn, a temperature Tn, and a charging rate Cn of the battery at the current sampling time point tn, and a voltage Vi of the battery at a sampling time point ti, and calculating a voltage difference Vn−Vi between the voltage Vn and the voltage Vi; (c) when the voltage difference Vn−Vi is greater than or equal to a preset voltage threshold, calculating a voltage change rate; and (d) when the voltage change rate is greater than or equal to a preset voltage change rate threshold for the first time, acquiring a corrected state of charge of the battery as an actual state of charge of the battery.

The present invention relates to a method for determining a state of charge of a battery, including: (a) acquiring a state of charge of the battery at a current sampling time point tn; (b) acquiring a voltage Vn, a temperature Tn, and a charging rate Cn of the battery at the current sampling time point tn, and a voltage Vi of the battery at a sampling time point ti, and calculating a voltage difference Vn−Vi between the voltage Vn and the voltage Vi; (c) when the voltage difference Vn−Vi is greater than or equal to a preset voltage threshold, calculating a voltage change rate; and (d) when the voltage change rate is greater than or equal to a preset voltage change rate threshold for the first time, acquiring a corrected state of charge of the battery as an actual state of charge of the battery.

The charge control circuit includes a cell connection detection circuit monitoring a voltage between input ports to which terminals of a cell pack are connected, an overvoltage detection circuit monitoring an overvoltage of the secondary cells, a first latch circuit receiving a signal output by the cell connection detection circuit, a second latch circuit receiving a signal output by the overvoltage detection circuit, a reset circuit outputting a signal to the first latch circuit and the second latch circuit when the charge control circuit is activated, and a control circuit receiving a signal output from the second latch circuit and outputting a signal for protecting the cell pack from the overvoltage. The control circuit does not output a signal for blowing the fuse until the first latch circuit receives a detection signal of the cell connection detection circuit.

The charge control circuit includes a cell connection detection circuit monitoring a voltage between input ports to which terminals of a cell pack are connected, an overvoltage detection circuit monitoring an overvoltage of the secondary cells, a first latch circuit receiving a signal output by the cell connection detection circuit, a second latch circuit receiving a signal output by the overvoltage detection circuit, a reset circuit outputting a signal to the first latch circuit and the second latch circuit when the charge control circuit is activated, and a control circuit receiving a signal output from the second latch circuit and outputting a signal for protecting the cell pack from the overvoltage. The control circuit does not output a signal for blowing the fuse until the first latch circuit receives a detection signal of the cell connection detection circuit.

In some examples, apparatus comprises a multiplexer (MUX) adapted to be coupled to a set of battery cells and configured to provide a voltage of a different battery cell in the set of battery cells based on a MUX control signal. Apparatus comprises a comparator coupled to the MUX and configured to compare a MUX output signal to a threshold voltage to provide a comparator output signal. Apparatus comprises a digital control circuit configured to provide the MUX control signal to the MUX, to store the comparator output signal, and to use a logic AND gate to provide an AND gate output signal based on the stored comparator output signal.

In some examples, apparatus comprises a multiplexer (MUX) adapted to be coupled to a set of battery cells and configured to provide a voltage of a different battery cell in the set of battery cells based on a MUX control signal. Apparatus comprises a comparator coupled to the MUX and configured to compare a MUX output signal to a threshold voltage to provide a comparator output signal. Apparatus comprises a digital control circuit configured to provide the MUX control signal to the MUX, to store the comparator output signal, and to use a logic AND gate to provide an AND gate output signal based on the stored comparator output signal.

A system for mitigating thermal runaway in a battery-powered electric vehicle (EV). The system includes a gas sensor configured to measure a level of at least one type of gas in a vicinity of a battery of the EV, a thermal event detector configured to determine, based on the measured level of the at least one type of gas, that the battery is experiencing out-gassing, and a communications interface configured to transmit an alert to a fleet management system regarding the out-gassing of the battery. The fleet management system alters an assignment of the EV in response to the out-gassing of the battery.

A system for mitigating thermal runaway in a battery-powered electric vehicle (EV). The system includes a gas sensor configured to measure a level of at least one type of gas in a vicinity of a battery of the EV, a thermal event detector configured to determine, based on the measured level of the at least one type of gas, that the battery is experiencing out-gassing, and a communications interface configured to transmit an alert to a fleet management system regarding the out-gassing of the battery. The fleet management system alters an assignment of the EV in response to the out-gassing of the battery.

A method for measuring a complex impedance of a plurality of battery cells in a battery pack comprises controlling an excitation current through the plurality of battery cells in the battery pack; receiving, in a single common measurement circuit, a plurality of voltage signals corresponding to the plurality of battery cells; measuring the excitation current; and calculating a complex impedance of each of the battery cells in the plurality of battery cells based on the plurality of voltage signals and the measured excitation current in a single measurement cycle using either one analog-to-digital converter (ADC) per battery cell or two matched ADCs per battery cell.