Abstract: A method and apparatus for monitoring an internet-of-things (IoT) battery device (IBD). An example IBD includes a radio transceiver to communicate with an IoT charging device (ICD), a battery, and a battery monitor to determine a state of charge for the battery. An alerter is included to send an alert message to the ICD, via the radio transceiver, to indicate that the SoCh is less than an alert threshold.

Abstract: A power supply device is provided with a disconnection means (AND element) for forcibly disconnecting a battery module from a series connection regardless of a gate signal. The power supply device forcibly disconnects partial battery modules from the series connection by the disconnection means (AND element) during powering by a power supply output, thereby performing control so that the accumulated discharge current amounts thereof per unit time become smaller than those of the other battery modules.

Abstract: A used secondary battery module management system server manages a manufacture of a battery assembly. The server stores, in a memory, a correspondence relationship of each of secondary battery modules among identification information, ranks, and status information. The server extracts an available rank from the ranks in response to a rebuilding request for the battery assembly. The available rank is a rank in which the number of the secondary battery modules having the status information indicating that the secondary battery modules are available is equal to or larger than the number of the secondary battery modules required to constitute the battery assembly. The server receives, from an external terminal, the identification information on each of selection secondary battery modules having an identical rank.

Abstract: An apparatus and a method for processing battery cell voltage data, which calculate a moving average by assigning a weight to one or more voltage data acquired from the battery cell and reflect the acquired voltage data to the calculated moving average and use the voltage data to rapidly follow a sudden change of the voltage data applied from the battery cell.

Abstract: An apparatus structured to control an electric vehicle accessory of an electric vehicle during a charge event includes a controller communicatively coupled to a battery and an electric vehicle accessory. The controller is structured to determine that the battery of an electric vehicle is undergoing a charge event, and based on determining that the battery of the electric vehicle is undergoing the charge event, place the electric vehicle accessory in an on-state during the charge event, and cause the electric vehicle accessory to recharge by absorbing energy from the charging station during the charge event.

Abstract: A vehicle includes an electric machine, a battery, an electrical circuit, an overcharge limit device, and a controller. The electric machine is configured to propel the vehicle. The battery has a plurality of cells and is configured to provide electrical power to the electric machine. The electrical circuit is configured to deliver the electrical power from the battery to the electric machine. The overcharge limit device is configured to individually disconnect each of the plurality cells from the circuit in response to an internal pressure of a respective cell exceeding a pressure threshold. The controller is programmed to, in response to detecting a first set of parameters that are indicative of a first of the cells being disconnected from the electrical circuit via the overcharge limit device, discontinue control the first of the cells.

Abstract: Provided are a battery state measuring method and battery management system, which predict a time point when charging capacity of a battery is to be relatively abruptly reduced. The battery state measuring method includes: monitoring a change of at least one precursor related to the charging capacity of the battery with respect to a number of charging cycles undergone by the battery; and predicting that an abrupt reduction in the charging capacity of the battery is imminent when the change of the at least one precursor follows at least one pre-configured pattern of the battery that has undergone a critical number of charging cycles.

Abstract: Various embodiments of the present technology may comprise methods and apparatus to determine an RSOC value of a battery. The methods and apparatus may comprise utilizing various parameters, such as voltage and/or current, to calculate the RSOC of the battery. In various embodiments, the methods and apparatus may display one of a first RSOC and a second RSOC. In various embodiments, the methods and apparatus may further detect changes in the relevant parameter(s), adjust a previously-reported RSOC of the battery accordingly, and report the adjusted RSOC.

Abstract: Systems, apparatuses, and methods disclosed provide for receiving internal information, external static information, and external dynamic information of a hybrid vehicle, and selectively enable or disable a stop/start function for the engine of the hybrid vehicle based on the internal hybrid vehicle information, external static information, and external dynamic information. The stop/start function controls selective activation and deactivation of the engine during operation of the hybrid vehicle.

Abstract: In one embodiment, a method includes, by a computing system of a vehicle, determining a first temperature of a control unit of the vehicle, wherein the control unit and one or more components of the vehicle are interconnected through a thermal network, determining a thermal objective for the control unit based on the first temperature of the control unit, selecting, based on the thermal objective for the control unit, at least a first component from the one or more components, and sending one or more signals to one or more actuators within the thermal network to enable a heat-transfer fluid to flow between (1) a first portion of the thermal network thermally coupled to the control unit and (2) a second portion of the thermal network thermally coupled to the selected first component.

Abstract: A battery management system may include: a charge control switch disposed in a high current path between a plurality of pack terminals and a battery module; and a controller configured to detect a cell voltage of each of a plurality of cells included in the battery module and a charging current flowing through a high current path, to determine an overvoltage state of the battery module based on presence or absence of the charging current and the cell voltage of each of the cells, and to turn off the charge control switch when the battery module is determined to be in an overvoltage state.

Abstract: One embodiment of the present disclose describes systems and methods responsible for reducing errors in a battery model used in the operation of a battery control system. The battery control system may operate based on a modeled response of the battery derived from the battery model. If the battery model is not calibrated/validated, errors in the battery model may propagate through the modeled response of the battery to the operation of the battery control system. A calibration current pulse may result in a different measured response of the battery than the modeled response of the battery to the same calibration current pulse. A validation technique, which uses a difference between the modeled response and the measured response of the battery to the calibration current pulse as a method to calibrate the battery model, may protect the battery control system from the contribution of errors from an uncalibrated battery model.

Abstract: An apparatus and a method for managing a battery are based upon degradation determination of the battery. The method includes determining a charging method when starting charging of a battery, storing at least one of a charge voltage, charge current, and temperature when starting charging of the battery, and when the determined charging method is constant current (CC) charging, determining a state of health (SOH) of the battery by comparing an increase in charge capacity of the battery with respect to an increase in charge voltage of the battery with a CC-section SOH mapping table, or when the determined charging method is constant voltage (CV) charging, determining the SOH of the battery by comparing at least one of an increase in the charge capacity of the battery and a charge time of the battery with a CV-section SOH mapping table.

Abstract: A fractional-order KiBaM battery model considering nonlinear capacity characteristics and a parameter identification method includes a temporary capacity portion and an available capacity portion for describing nonlinear capacity characteristics of a battery, wherein the temporary capacity portion represents the power that can be directly obtained during the discharge, indicating the state of charge (SOC) of the battery; the available capacity portion represents the power that cannot be directly obtained, and such two portions are connected; when the battery is discharged, the load current i flows out from the temporary capacity portion, and a power passing rate coefficient of such capacity portions is obtained; and the nonlinear capacity effect and recovery effect of the battery are denoted by the height ratio of the temporary capacity and available capacity portions in view of the magnitude of the fractional order of battery capacity characteristics.

Abstract: The invention relates to a method for aging-optimized charging of an energy store of a motor vehicle, comprising: detecting a predetermined number of consecutive full charging processes of the energy store; creating a use profile of the energy store on the basis of discharging processes of the energy store between the consecutive full charging processes; determining whether the created use profile requires a full charging process as the next charging process, and, if the created use profile does not require a full charging process as the next charging process, proposing the charging strategy for the aging-optimized charging, wherein the charging strategy specifies a partial charging process of the energy store for at least the next charging process, in which the energy store is charged up to a predetermined partial charging limit of the operating capacity of the energy store that is smaller than the full charging limit.

Abstract: A learning apparatus includes: a learning part that performs, based on charging/discharging data indicating at least one of charging and discharging of a secondary battery that supplies electric power for traveling of a vehicle, a capacity learning of the secondary battery and that performs the capacity learning in response to a change amount of a charging rate that is indicated by the charging/discharging data exceeding a threshold value; and a threshold determination part that determines the threshold value based on history information of the learning part performing the capacity learning in a predetermined period.

Abstract: A vehicle battery charger and a vehicle battery charging system are described and illustrated, and can include a controller enabling a user to enter a time of day at which the vehicle battery charger or system begins and/or ends charging of the vehicle battery. The vehicle battery charger can be separate from the vehicle, can be at least partially integrated into the vehicle, can include a transmitter and/or a receiver capable of communication with a controller that is remote from the vehicle and vehicle charger, and can be controlled by a user or another party (e.g., a power utility) to control battery charging based upon a time of day, cost of power, or other factors.

Abstract: A secondary battery system and a secondary battery control method, wherein the system and the method include a plurality of unit cells connected in series, and a recovery charging controller that performs recovery charging of charging the plurality of unit cells while generating a micro short-circuit in at least one of the plurality of unit cells by charging the plurality of unit cells at a predetermined recovery charging current value which is higher than a upper limit current value during normal charging, wherein the unit cells are all-solid-state lithium secondary battery unit cells.

Abstract: A geophone, and method for distributing geophones around a seismic data source are described. The geophone includes a housing, a spike provided on a bottom surface of the housing, a sensor configured to sense seismic data; a processor configured to process the seismic data, a transceiver configured to transmit the processed seismic data and receive radio frequency (RF) signals wirelessly; and a power device. The power device is coupled to the sensor, the processor and the transceiver. The power device is configured to harvest energy from an environment where the geophone is located. The power device includes a solar cell provided on a top surface of the housing, a piezoelectric system provided on an edge of the housing adjacent to the top surface, and a thermoelectric generator provided on a bottom surface of the housing and a surface of the spike.

Abstract: A battery state estimating apparatus including a voltage measuring unit configured to measure a voltage of a battery cell and measure an open circuit voltage (OCV) of the battery cell whenever the measured voltage reaches a reference charge voltage, and a control unit configured to receive the OCV measured by the voltage measuring unit, calculate a voltage fluctuation rate based on a result obtained by processing the received OCV, determine a voltage increase and decrease pattern based on the calculated voltage fluctuation rate and pre-stored voltage fluctuation rate data, and determine a degradation acceleration degree of the battery cell according to the determined voltage increase and decrease pattern.

Abstract: Systems and methods for monitoring the health of a vehicle battery are described, in which an example vehicle includes a vehicle battery, one or more vehicle battery sensors, and a processor. The processor is configured to determine a battery health metric of the vehicle battery, wherein the battery health metric is based on a battery service time, a battery state of charge, and a battery temperature. The processor is also configured to perform a battery refresh operation on the vehicle battery responsive to determining that the battery health metric is above a refresh threshold. And the processor is further configured to activate a vehicle alert responsive to determining that the battery health metric is above an end-of-life threshold.

Abstract: Provided is a system for constructing mobile electric energy interconnection. The system includes at least one mobile electric energy exchange device, a mobile electric energy interconnection management platform and at least one stationary electric energy interconnection device. The mobile electric energy interconnection management platform is configured to match the at least one mobile electric energy exchange device with the at least one stationary electric energy interconnection device, and push a matching result to the at least one mobile electric energy exchange device and the at least one stationary electric energy interconnection device. Also provided is a method for constructing mobile electric energy interconnection, a data testing method and device, and a computer readable storage medium.

Abstract: According to one embodiment, a remanufacturing support server includes processor. The processor is configured to: acquire specification data representing required performance of a battery product; set an allowable range of a degradation state of a secondary battery to be used in the battery product; acquire diagnostic data indicating a diagnostic result of a degradation state of a secondary battery mounted on a vehicle, the diagnostic result of the degradation state of the secondary battery falling within the allowable range as the battery product; and provide an outside with a remanufacturing plan relating to the battery product based on the diagnostic data.

Abstract: The present disclosure relates to systems, devices, and methods for analyzing health of vehicle batteries. Vehicle batteries tend to degrade over time. The described systems, devices, and methods quantify this degradation (or quantify remaining health of the battery) by comparing average energy used to charge or discharge the battery by a charge level unit to a nominal quantity of energy used to charge or discharge a battery in optimal health by a charge level unit. Charge data for previous charge events of the vehicle battery can be used in the calculation, and can be filtered by identifying qualified charge events based on at least one of a number of metrics. Usage data for previous usage events of the vehicle battery can be used in the calculation, and can be filtered by identifying qualified usage events or subgroups of usage event based on at least one of a number of metrics.

Abstract: A power control system for an electric vehicle without a start manipulator, and a method therefor, includes a communication device that performs wireless communication with an electronic key and a body controller connected with the communication device. The body controller determines a power control mode as a factory mode or an electronic key discharge mode based on whether an electronic key is learned and whether a battery of the electronic key is discharged and controls vehicle power transition depending on power transition logic matched to the determined power control mode.

Abstract: A scheme is provided for dynamically adjusting an amount of power drawn from individual power sources to optimize the power usage without violating power limits. Coarse adjustment is provided through dynamic phase reallocation while a fine adjustment is provided through dynamic current steering. By adding a control loop around current steering techniques in digital voltage regulator controllers, power drawn from multiple input rails is balanced. The apparatus allows users to maximize the power delivered to discrete graphics cards without violating PCIe specifications. This allows maximum performance with minimal bill-of-material (BOM) cost.

Abstract: A secondary battery (10) of the present invention includes at least a positive electrode (11), a negative electrode (12), a separation layer (5) that spatially separates the positive electrode (11) and the negative electrode (12), and an ion conductor that is held between the positive electrode (11) and the negative electrode (12) and has a function of conducting ions between the positive electrode (11) and the negative electrode (12).

Abstract: A battery diagnostic device includes: an acquisition unit that acquires a temperature and an internal resistance of a battery; a determination unit that determines a diagnostic temperature that is a temperature used for a diagnosis of the battery, based on the temperature acquired by the acquisition unit; an estimation unit that estimates the internal resistance of the battery at the diagnostic temperature based on the temperature and the internal resistance acquired by the acquisition unit and the diagnostic temperature determined by the determination unit; and a diagnosis unit that diagnoses the battery based on the internal resistance estimated by the estimation unit.

Abstract: The present disclosure relates to a charging control system for an electric vehicle including: an input device for receiving inputs of a demanded charge amount of a battery so as to charge the battery by using a charger; a processor configured to compute an expected charge time required to charge the battery and an expected drivable distance on completion of charging based on the demanded charge amount input to the input device; and an output device for displaying the expected charge time and the expected drivable distance computed by the processor.

Abstract: Testing of a battery module can be conducted using monitoring electronics attached to the battery module. Stimulus can be applied to the battery module and removed. After removal of the stimulus, the monitoring electronics can collect signals from the monitoring electronics reflecting parameters of the battery module as it relaxes back to a non-stimulated state. The stimulus can be provided by test equipment or by components of a system in which the battery module, having attached monitoring electronics, is implemented. The monitoring electronics attached to the battery module can provide autonomous recording of signals associated with the battery module that can provide data regarding the status of the battery module or one or more batteries contained in the battery module.

Abstract: An electric storage system to which a first electric storage device and a second electric storage device connected in parallel can be mounted decides a rated voltage of the first electric storage device in an electric storage system having at least one of (A) a discharge standby stage and (B) a charge standby stage. It decides a large and small relationship between the rated voltage of the electric storage device for which at least one of (i) an accumulated time, (ii) an accumulated power amount, and (iii) an accumulated number is decided to be made higher among the first electric storage device and the second electric storage device, and the rated voltage of the other electric storage device. It decides the rated voltage of the first electric storage device such that the large and small relationship decided in the large and small relationship deciding step is achieved.

Abstract: A control system for a vehicle to prevent a reduction in a drive force due to increase in an internal resistance of a battery. A controller calculates a command value of an output power of the battery to be transmitted to a motor in future, and predicts an internal resistance of the battery at the point to discharge the electric power from the battery in the amount of the command value. If it is expected that the battery will not be possible to discharge the electric power in the amount of the command value, the controller reduces a load on the battery by increasing an amount of the electric power supplied to the motor from the generator before the battery can no longer discharge the electric power in the amount of the command value.

Abstract: Apparatuses, systems, and methods are presented for battery charging. A charging connector may connect to power terminals of a battery. A data connector may connect to a battery. A charger controller may read battery data from a battery via a data connector, set a completion threshold based on the battery data, and charge the battery via a charging connector until the completion threshold is satisfied.

Abstract: An automotive battery module having dual voltage is disclosed, including a housing and a plurality of battery cells connected to form battery cell blocks disposed in the housing. A battery control unit is provided disposed in the housing and is configured to control operation of a battery system. The battery system includes at least one switching device operably connected to a first battery cell block in a first connection arrangement. The first battery cell block is configured to deliver a first voltage. The switching device is also operably connected to a second battery cell block in a second connection arrangement. The second battery cell block is configured to deliver a second voltage. A plurality of terminals are provided on the housing and electrically coupled to the battery control unit and plurality of battery cells, providing an external electrical connection to deliver the first voltage and the second voltage.

Abstract: A method of estimating a deteriorated state of a battery includes steps S102 to S110. S102 is a step of obtaining a voltage and a current of the battery a plurality of times for a data acquisition period. S104 is a step of calculating an amount of change in current, an amount of change in temperature, and an amount of change in SOC during the data acquisition period. S106 is a step of obtaining an allowable amount of change in current, an allowable amount of change in temperature, and an allowable amount of change in SOC based on an average temperature. S110 is a step of calculating an impedance component for each frequency bandwidth based on the voltage and the current by subjecting the voltage and the current to Fourier transform when all amounts of change are smaller than the allowable amounts of change.

Abstract: According to embodiments, a wireless charging coil and an electronic device including the same are provided. The electronic device may include a battery; a wireless charging coil; a wireless charging circuit configured to wirelessly transmit and/or receive power using the wireless charging coil; and a processor electrically connected to the battery, the wireless charging coil, and the wireless charging circuit, wherein based on another electronic device being positioned within a specified transmission and/or reception distance of the electronic device, the processor is configured to control the electronic device to transmit power stored in the battery to the other electronic device using the wireless charging coil and the wireless charging circuit. Therefore, the electronic device can wirelessly charge another electronic device, a watch, and an earbud in which the remaining battery capacity is insufficient.

Abstract: A method for estimating a state of a battery pack using a controller having battery state estimator (BSE) logic includes receiving or delivering a constant baseline current via the battery pack. Current oscillations having time-variant frequency content are selectively injected into the baseline current via the controller in response to a predetermined condition. The baseline current and the current oscillations combine to form a final current. The method includes estimating a battery parameter via the BSE logic concurrently with the current oscillations to generate an estimated battery parameter, and estimating the present state of the battery pack via the controller using the estimated battery parameter. An electrical system includes a rotary electric machine that is electrically connected to and driven by the battery pack, and a controller configured to execute the method.

Abstract: A battery system includes a controller that performs a calculation to calculate an internal resistance of a battery, and executes a predetermined operation based on the result. The calculation includes obtaining a regression line through a regression analysis of a current-voltage plot obtained from voltage sensor and current sensor, and calculating the internal resistance from a slope of the regression line. The controller calculates a first internal resistance through the calculation based on a first group of detection values of the voltage and current detected a plurality of times, and calculate a second internal resistance through the calculation based on a second group of detection values. The controller executes the predetermined operation when a resistance difference between the first and second internal resistances is smaller than a reference value, and does not execute the operation when the resistance difference is larger than the reference value.

Abstract: A device for estimating state of charge of battery of the present disclosure includes: a sensing unit configured to measure at least one of a first voltage and an OCV of a battery; and a processor operably coupled to the sensing unit. The processor is configured to estimate a second voltage of the battery based on the OCV of the battery or a previously estimated first SOC, calculate a counted voltage error by counting a voltage error between the first voltage and the second voltage of the battery, correct the second voltage of the battery depending on whether the counted voltage error is included in a reference error range, and estimate a first SOC of the battery based on the second voltage or the corrected second voltage.

Abstract: A device having a structure to measure a battery parameter of a battery of a set of multiple batteries can be implemented in a variety of applications. The device can be structured to measure alternating current (AC) electrical impedance of a battery cell by processing a difference between the battery cell and another battery cell. The battery cell being measured is subjected to AC excitation while the other one is not, where the two battery cells share a common load current. This differencing method can reduce the measurement's sensitivity to noisy battery load current, which is common to both battery cells. This differencing method also can remove or substantially reduce a large direct current (DC) offset, that is, the battery potential itself under which the AC signal measurement is burdened.

Abstract: Systems and methods for compensating battery health readings at low temperatures are described. In some embodiments, an Information Handling System (IHS) may include: a processor and a memory coupled to the processor, the memory having program instructions stored thereon that, upon execution by the processor, cause the IHS to: calculate a state-of-health (SOH) of a battery, and compensate the SOH, at least in part, by taking into account at least one temperature measured during a charge cycle.

Abstract: A controller for use in a battery charging system includes processing circuitry configured to perform certain tasks during battery charging operations, and other tasks during operational use of the battery. During a charging operation, the controller receives a measured DC impedance of a propulsion battery measured by a battery data acquisition and monitoring subsystem, obtains a reference DC impedance of a hypothetical battery, and determines an impedance degradation factor of the propulsion battery using the measured DC impedance and the reference DC impedance. During operational use of the propulsion battery, the controller obtains an operational reference impedance of the propulsion battery, determines a real-time effective impedance for the propulsion battery based on the impedance degradation factor and the operational reference impedance, and generates a feed-forward parameter based on the real-time effective impedance.

Abstract: Provided are a method and system for determining State of Health (SOH) of a battery. The method includes: detecting a charging state of the battery that is being charged by a Constant Current (CC) or a Constant Voltage (CV); adding a low frequency current signal to the CC that is charging the battery to obtain a low frequency charging current, or adding a low frequency voltage signal to the CV, that is charging the battery to obtain a low frequency charging voltage; determining one or more parameters relating to the battery during the charging state of the battery; calculating an internal impedance and Open Circuit Voltage (OCV) values based on the one or more parameters; and determining SOH of the battery based on the calculated internal impedance and the OCV values.

Abstract: A portable charging case is provided. The case includes a charging interface configured to establish a power transfer connection with a wireless audio device having a battery. The case includes charging circuitry configured to determine a voltage of the battery. The charging circuitry is further configured to, if the voltage is less than or equal to an undervoltage lockout, charge the battery in pre-charging mode. In pre-charging mode, the charging circuitry is configured to apply a constant pre-charging voltage to the battery. The charging circuitry is further configured to switch from pre-charging mode to standard charging mode when the voltage exceeds the undervoltage lockout value. The charging circuit is further configured to determine the voltage by (1) powering on, via a case power source, the wireless audio device; (2) applying, pre-charge load to the device battery; (3) retrieving the voltage; and (4) transmitting the voltage to the case.

Abstract: The present disclosure provides a wireless charging device, an electronic device, a wireless charging system and a wireless charging method. The wireless charging device includes: a transmitting coil; a first communication circuit, configured to receive relative position information of a receiving coil of a device to be charged; a plurality of prompters, the plurality of prompters being arranged around the transmitting coil; and a controller, configured to generate a trigger instruction of the prompter, according to the relative position information in combination with a relative positional relationship between the plurality of prompters and the transmitting coil, and control the prompter at a corresponding position to be turned on, to indicate a placement position of the device to be charged, so as to align the transmitting coil and the receiving coil.

Abstract: Embodiments of the present disclosure provide a charging method for multiple cells. The method includes: converting a received charging voltage to obtain a converted charging voltage; and charging multiple cells connected in series with the converted charging voltage. The technical solution according to embodiments of the present disclosure reduces the charging current and the heat generated by a terminal during the charging process. Meanwhile, when the charging current remains the same, the charging voltage is increased, achieving fast charging.

Abstract: A battery capacity estimation apparatus including: a battery; a sensing unit connected to the battery to measure an OCV of the battery; an SOC estimation unit connected to the sensing unit to estimate an SOC of the battery using the OCV measured from the sensing unit; a memory unit storing data including the SOC and the OCV of the battery, the memory unit being connected to the SOC estimation unit; and an operation unit connected to the SOC estimation unit and the memory unit, the operation unit being configured to calculate an SOC reduction degree according to a use voltage range change and re-calculate a changed SOC according to a changed use capacity.

Abstract: A vehicle battery controller includes a sensor configured to acquire information on a subordinate battery configured to back up a main battery during autonomous driving, a DDC provided between the main battery and the subordinate battery, a switching circuit configured to switch a connection state of the subordinate battery between a connection state for manual driving and a connection state for the autonomous driving, and an electronic control unit configured to control charging and discharging of the subordinate battery by controlling the DDC and the switching circuit based on the information acquired by the sensor. The electronic control unit permits the autonomous driving when determination is made, through first battery control, that the subordinate battery can output backup power. The electronic control unit determines whether the subordinate battery can output the backup power by executing second battery control having higher accuracy than that of the first battery control.

Abstract: Disclosed in the present invention are a method for controlling multi-mode charging, a mobile terminal, and a storage medium. The method comprises: pre-configuring multiple charging modes; connecting a charger, and receiving a user operation instruction, the operation instruction comprising a mode selection instruction; configuring and starting a timer according to a preset charging mode and the received operation instruction; and disabling or enabling a charging function when the time period set in the timer has passed.

Abstract: The economic efficiency estimation apparatus of the rechargeable battery and the economic efficiency estimation method thereof according to the present invention estimate an economic efficiency index correlated with a full-charge capacity and a charge/discharge energy quantity of a secondary battery, by using a voltage difference between a discharge voltage, which is precalculated, and a charge maximum voltage.