A battery monitoring system continuously calculates the estimated runtime of a bank of batteries in a battery backup system during both a period of operation when the load current is supplied by a commercial source of AC power and during a period of operation when the commercial source of AC power is not present and the load current is supplied by the bank. The estimated runtime may be displayed to an operator and used to alert the operator if the cutoff voltage of a battery in the bank is at or near its cutoff voltage. The system may open a circuit breaker to avoid catastrophic damage before the cutoff voltage is reached.

A method of determining state of health (SoH) of a battery is disclosed which includes receiving a predetermined open circuit voltage (V.sub.OC) vs. a state of charge (SoC) characteristics for a pristine battery, establishing a single battery model including physical diffusion characteristics and electrical characteristics based on lumped parameters thereby modeling diffusion resistance and capacitance of particles in the electrodes of the battery as well as electrical characteristics based on electrical resistance and capacitance from one electrode assembly to another, thereby generating equations describing voltage at the associated double-layers, solving the double-layer equations, thereby generating solutions for the double-layer electrical characteristics, and establishing a relationship between the solved double-layer characteristics and the SoC, thereby determining a SoH of the battery based on said relationship.

A method of determining state of health (SoH) of a battery is disclosed which includes receiving a predetermined open circuit voltage (V.sub.OC) vs. a state of charge (SoC) characteristics for a pristine battery, establishing a single battery model including physical diffusion characteristics and electrical characteristics based on lumped parameters thereby modeling diffusion resistance and capacitance of particles in the electrodes of the battery as well as electrical characteristics based on electrical resistance and capacitance from one electrode assembly to another, thereby generating equations describing voltage at the associated double-layers, solving the double-layer equations, thereby generating solutions for the double-layer electrical characteristics, and establishing a relationship between the solved double-layer characteristics and the SoC, thereby determining a SoH of the battery based on said relationship.

A battery model construction method includes: a step ST2 for constructing a battery model; steps ST3 and ST4 for evaluating, for each sample battery, the prediction error between a measured value of the SOH and a predicted value according to the battery model, and determining whether there is inherent bias in the prediction error for each sample battery; steps ST5 and ST6 for constructing a first error prediction model associating explanatory variables defined on the basis of usage history parameters with an objective variable, and determining whether a first correlation exists between the measured value of the average prediction error acquired in steps ST3 and ST4 and the predicted value according to the first error prediction model; and a step ST7 for reconstructing the battery model in the case where it is determined that there is bias and that the first correlation exists in steps ST5 and ST6.

A battery model construction method includes: a step ST2 for constructing a battery model; steps ST3 and ST4 for evaluating, for each sample battery, the prediction error between a measured value of the SOH and a predicted value according to the battery model, and determining whether there is inherent bias in the prediction error for each sample battery; steps ST5 and ST6 for constructing a first error prediction model associating explanatory variables defined on the basis of usage history parameters with an objective variable, and determining whether a first correlation exists between the measured value of the average prediction error acquired in steps ST3 and ST4 and the predicted value according to the first error prediction model; and a step ST7 for reconstructing the battery model in the case where it is determined that there is bias and that the first correlation exists in steps ST5 and ST6.

One or more systems, devices, and/or system-implemented methods are provided that can facilitate provision of varying AC output voltage or DC output voltage, including selectively separately providing a positive voltage output, a negative voltage output and no voltage output. A device can comprise a battery cell, and a controller connected to the battery cell and that varies output from the battery cell, wherein the controller is configured to cause the battery cell to selectively separately provide negative output voltage, positive output voltage and no output voltage. A method can comprise varying output polarity from a multi-cell battery cluster and selectively providing one or both of alternating current (AC) voltage output or direct current (DC) voltage output from the multi-cell battery cluster due to the varying of the output polarity.

One or more systems, devices, and/or system-implemented methods are provided that can facilitate provision of varying AC output voltage or DC output voltage, including selectively separately providing a positive voltage output, a negative voltage output and no voltage output. A device can comprise a battery cell, and a controller connected to the battery cell and that varies output from the battery cell, wherein the controller is configured to cause the battery cell to selectively separately provide negative output voltage, positive output voltage and no output voltage. A method can comprise varying output polarity from a multi-cell battery cluster and selectively providing one or both of alternating current (AC) voltage output or direct current (DC) voltage output from the multi-cell battery cluster due to the varying of the output polarity.

A method for determining charging profiles for device batteries of battery-operated devices. In one instance, the method includes selecting device batteries having the same usage-related load and the same aging state; dividing the selected device batteries into groups; assigning different charging profiles to the groups of device batteries, wherein the charging profiles indicate for a charging operation a maximum permissible charging current depending on a charge level range; operating the device batteries of all groups with the respectively assigned charging profiles for a predetermined period of time, so that charging operations are executed depending on the respectively assigned charging profile; detecting a change in the average aging state for each group of device batteries between the beginning of the predetermined time period and the end of the predetermined time period; and adjusting the charging profile depending on the change in the average aging state.

A method for determining charging profiles for device batteries of battery-operated devices. In one instance, the method includes selecting device batteries having the same usage-related load and the same aging state; dividing the selected device batteries into groups; assigning different charging profiles to the groups of device batteries, wherein the charging profiles indicate for a charging operation a maximum permissible charging current depending on a charge level range; operating the device batteries of all groups with the respectively assigned charging profiles for a predetermined period of time, so that charging operations are executed depending on the respectively assigned charging profile; detecting a change in the average aging state for each group of device batteries between the beginning of the predetermined time period and the end of the predetermined time period; and adjusting the charging profile depending on the change in the average aging state.

A highly safe power storage system is provided. If n (n is an integer over or equal to three) secondary batteries are used in a vehicle such as an electric vehicle, a circuit configuration is used with which the condition of each secondary battery is monitored using an anomaly detection unit; and if an anomaly such as a micro-short circuit is detected, only the detected anomalous secondary battery is electrically separated from the charging system or the discharging system. At least one microcomputer monitors anomalies in n secondary batteries consecutively, selects the anomalous secondary battery or the detected secondary battery which causes an anomaly, and gives an instruction to bypass the secondary battery with each switch.