A system includes a state of charge (SOC) calculation module configured to calculate an SOC of a battery cell based on a measured current of the battery cell and an overpotential calculation module configured to receive the measured current and output lagged currents based on the measured current and respective time constants, output a weighted measured current and weighted lagged currents based on a plurality of weighting factors, wherein a sum of the plurality of weighting factors is 1, calculate an equivalent constant current corresponding to the measured current based on the weighted measured current and the weighted lag currents, and calculate an overpotential of the battery cell based on the equivalent constant current. The system is configured to output a predicted voltage of the battery cell based on the calculated SOC and the calculated overpotential of the battery cell.

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.

The battery degradation detection device includes an impedance measurement unit and a degradation detection unit. The impedance measurement unit measures impedances of a battery at a plurality of frequencies. The impedance for at least one of the plurality of frequencies, measured by the impedance measurement unit, has a positive imaginary component. The degradation detection unit detects degradation of the battery on the basis of real components of the impedances at the plurality of frequencies detected by the impedance measurement unit.

The battery degradation detection device includes an impedance measurement unit and a degradation detection unit. The impedance measurement unit measures impedances of a battery at a plurality of frequencies. The impedance for at least one of the plurality of frequencies, measured by the impedance measurement unit, has a positive imaginary component. The degradation detection unit detects degradation of the battery on the basis of real components of the impedances at the plurality of frequencies detected by the impedance measurement unit.

Methods for determining a maximum duration of use of a battery, include: selecting a period of use of the battery; obtaining values of factors of degradation of the battery during the period of use of the battery selected during the selection step; determining at least one indicator of ageing of the battery on the basis of the degradation factor values obtained in the step of obtaining said values; and identifying intervals of variation of the degradation factors during said period of use, each ageing indicator being associated with actual variation intervals which each have a minimum value and a maximum value of said factors used during the determination step; and a step of predicting the maximum duration of use on the basis of the variation intervals obtained in the step of identification, the at least one ageing indicator and the operating limits of the battery.

Methods for determining a maximum duration of use of a battery, include: selecting a period of use of the battery; obtaining values of factors of degradation of the battery during the period of use of the battery selected during the selection step; determining at least one indicator of ageing of the battery on the basis of the degradation factor values obtained in the step of obtaining said values; and identifying intervals of variation of the degradation factors during said period of use, each ageing indicator being associated with actual variation intervals which each have a minimum value and a maximum value of said factors used during the determination step; and a step of predicting the maximum duration of use on the basis of the variation intervals obtained in the step of identification, the at least one ageing indicator and the operating limits of the battery.

A method for determining a state of charge of at least one battery cell, having the following steps to enable an improved determination of the state of charge of a lithium iron phosphate cell: generating an alternating current pulse in a circuit connected to the at least one battery cell, determining an impedance of the at least one battery cell on the basis of the alternating current pulse and determining the state of charge by comparing the impedance to predefined map data, wherein a relationship between the impedance and the state of charge of the at least one battery cell is determined from the predefined map data.

The invention provides a battery monitoring system comprising a battery monitoring device and at least one battery pack in storage. The battery pack comprises at least one battery core, a controller, and a temperature sensor. When the controller of the battery pack senses that a temperature of the battery core is higher than a safe temperature value, it issues an alarm signal, and directly transmits the alarm signal to the battery monitoring device in a short distance wireless communication, or transmits the alarm signal to the battery monitoring device via a multi-hop transmission of multiple battery packs in the short distance wireless communication. The alarm signal received by the battery monitoring device will be displayed on an alarm notification unit. Accordingly, the battery monitoring system can instantly monitor the temperature of the battery pack in storage to reduce the probability of burning or exploding of the battery pack.

A predictive energy monitoring system which, during discharge, accounts for changes in available energy remaining as a result of changes in battery environmental temperature, changes in energy used by systems which cycle on and off, and which provides a user “What-if” capability to predict energy availability time remaining by changing systems in use. The present invention also covers the reporting of re-charge completion against multiple re-charge goals. The battery monitoring system includes a non-volatile memory, sensors, a processor that receives inputs from the sensors and receives inputs from a user through a touch screen graphic user interface, the processor then makes calculations responsive to sensor inputs and user inputs, and supplies data to a display for presenting a plurality of screen images representing the results of the calculations.