Sensors and methods for determining the state of charge of a battery are described. The state of charge is determined in some instances by applying a current perturbation having a frequency to the battery terminals, monitoring the response signal, and determining the phase of the response signal. The phase may be correlated to the state of charge of the battery, so that once the phase is determined, a determination of the state of charge of the battery may be made. In some situations, the state of charge may be used to determine the operating condition of a load connected to the battery. In some embodiments, the state of charge may be used to determine whether the battery is defective.

Sensors and methods for determining the state of charge of a battery are described. The state of charge is determined in some instances by applying a current perturbation having a frequency to the battery terminals, monitoring the response signal, and determining the phase of the response signal. The phase may be correlated to the state of charge of the battery, so that once the phase is determined, a determination of the state of charge of the battery may be made. In some situations, the state of charge may be used to determine the operating condition of a load connected to the battery. In some embodiments, the state of charge may be used to determine whether the battery is defective.

A method for charging a nonaqueous electrolyte secondary battery includes a first charging step of charging a first capacity Q.sub.1st at a first constant current value I.sub.1st, the first capacity Q.sub.1st including a capacity range in which dQ.sub.Si/dQ is more than or equal to a predetermined threshold value, a second charging step of charging a second capacity at a second constant current value more than the first constant current value, a detection step of acquiring at least one of dV/dQ and dQ.sub.Si/dQ, and a changing step of changing at least one of the timing of switching between the first charging step and the second charging step and the first constant current value I.sub.1st on the basis of a change in time of dV/dQ or dQ.sub.Si/dQ.

A method for charging a nonaqueous electrolyte secondary battery includes a first charging step of charging a first capacity Q.sub.1st at a first constant current value I.sub.1st, the first capacity Q.sub.1st including a capacity range in which dQ.sub.Si/dQ is more than or equal to a predetermined threshold value, a second charging step of charging a second capacity at a second constant current value more than the first constant current value, a detection step of acquiring at least one of dV/dQ and dQ.sub.Si/dQ, and a changing step of changing at least one of the timing of switching between the first charging step and the second charging step and the first constant current value I.sub.1st on the basis of a change in time of dV/dQ or dQ.sub.Si/dQ.

A controller for controlling a charging current to a lithium-ion secondary battery controls the charging current so that lithium expected to dissolve after a stop of charging is permitted to deposit on an anode of the lithium-ion secondary battery. For example, the controller controls the charging current so that the charging current does not exceed a predetermined upper limit value. If a predetermined permission condition is satisfied, the controller permits the lithium expected to dissolve after the stop of charging to deposit on the anode of the lithium-ion secondary battery by permitting the upper limit value to become larger than a Li deposition limit value in a predetermined permission period.

A controller for controlling a charging current to a lithium-ion secondary battery controls the charging current so that lithium expected to dissolve after a stop of charging is permitted to deposit on an anode of the lithium-ion secondary battery. For example, the controller controls the charging current so that the charging current does not exceed a predetermined upper limit value. If a predetermined permission condition is satisfied, the controller permits the lithium expected to dissolve after the stop of charging to deposit on the anode of the lithium-ion secondary battery by permitting the upper limit value to become larger than a Li deposition limit value in a predetermined permission period.

Various embodiments manage a fuel cell IT grid system to maintain fuel cell temperatures above a threshold temperature. The system may include power modules each including a fuel cell, DC/DC converters each connected to a power module, a DC power bus connected to the DC/DC, IT loads each connected to the DC power bus, a load balancing load connected to the DC power bus, and a control device connected to a first power module. The control device may determine whether a temperature of the first power module exceeds the temperature threshold, determine whether an electrical power output of the power modules exceeds an electrical power demand of the IT loads in response to the temperature exceeding the temperature threshold, and direct excess electrical power output to the load balancing load in response to the electrical power output exceeding the electrical power demand.

The present disclosure relates to a method for predicting lifespan characteristics of a lithium secondary battery that can reliably predict the lifespan characteristics of a lithium secondary battery, specifically, the mode of variation in cycle capacity in advance.

The present disclosure relates to a method for predicting lifespan characteristics of a lithium secondary battery that can reliably predict the lifespan characteristics of a lithium secondary battery, specifically, the mode of variation in cycle capacity in advance.

A redox flow battery includes a cell that has first and second electrodes and an ion-exchange layer there between, first and second circulation loops that are fluidly connected with, respectively, the first and second electrodes, first and second electrolyte storage tanks in, respectively, the first and second circulation loops, first and second electrolytes contained in, respectively, the first and second circulation loops, and a Raman spectrometer on at least one of the first or second circulation loops for determining a state-of-charge of at least one of the first or second electrolytes. The Raman spectrometer includes a laser source that is rated to emit a laser of a wavelength of 694 nanometers to 1444 nanometers.