Abstract: A car battery system includes a plurality of battery cells, each battery cell having a positive electrode terminal and a negative electrode terminal, a battery block that retains the plurality of battery cells in a stacked configuration and has a terminal surface that is formed by battery cell terminal surfaces established by the positive and negative electrode terminals, and a battery state detection circuit that is connected to the electrode terminals of each battery cell to detect the condition of each battery cell. The positive and negative electrode terminals of each battery cell are connected to a circuit board and to the battery state detection circuit. The circuit board is connected to the positive and negative electrode terminals of each battery cell via voltage detection lines, and the voltage detection lines are connected to the same locations on the electrode terminals of each battery cell.

Abstract: Embodiments of the present invention provide a battery charging method, related to the field of electronic technologies and invented to shorten the charging time. The method includes: determining, by a mobile terminal, a specification parameter of a battery to be charged; determining, by the mobile terminal, a charging parameter corresponding to the specification parameter according to the determined specification parameter; and charging, by the mobile terminal, the battery to be charged according to the determined charging parameter. Embodiments of the present invention also provide a corresponding mobile terminal. The present invention is applicable to charging of a mobile terminal.

Abstract: A charging control device 10 that controls charging of a plurality of electric automobiles 208, 209, 210 includes: a charging determination unit 305 that determines whether or not a state of charge of the electric automobile 208, 209, 210 connected via a contactor 202, 203, 204 satisfies a predetermined condition, determines that the electric automobile is to be charged when the condition is satisfied, and determines that charging of the electric automobile is to be interrupted in order to charge another electric automobile when the condition is not satisfied; and a contactor control unit 302 that controls the contactor 202, 203, 204 on the basis of the determination of the charging determination unit 305.

Abstract: A battery charger is disclosed that is configured to be connected to an external battery by way of external battery cables. In accordance with an important aspect of the invention, the battery charger is configured with automatic voltage detection which automatically determines the nominal voltage of the battery connected to its battery charger terminals and charges the battery as a function of the detected nominal voltage irrespective of the nominal voltage selected by a user. Various safeguards are built into the battery charger to avoid overcharging a battery. For battery chargers with user selectable nominal battery voltage charging modes, battery charger is configured to over-ride a user selected battery voltage mode if it detects that the battery connected to the battery charger terminals is different than the user selected charging mode.

Abstract: An apparatus and method for displaying battery capacity and a charge/discharge state of a portable device are provided. The apparatus includes a charge Integrated Circuit (IC) for providing current to recharge the battery using an external charge power source, a sensing resistance interposed between the battery and the charge IC, a switch connected to the sensing resistance in parallel and opened to flow the current to the sensing resistance when a capacity of the battery is measured, and a controller for determining the capacity of the battery using voltage values at both ends of the sensing resistance measured when the switch is opened.

Abstract: The present invention generally relates to a thermal battery testing apparatus and a method for testing a thermal battery. The method includes one or more of the following steps: connecting the thermal battery in series with a resistance; connecting the thermal battery and resistance in series with a sinusoidal voltage source; applying a sinusoidal voltage to the thermal battery, measuring an impedance, reactance and/or capacitance across two terminals of the thermal battery, comparing the measured impedance, reactance and/or capacitance to a reference impedance, reactance and/or capacitance; and indicating whether the tested thermal battery is “in family” or “out of family.” The battery testing apparatus may include a testing device configured to apply a sinusoidal voltage to the thermal battery and to measure the impedance, reactance and/or capacitance across two terminals of the thermal battery. The testing apparatus may further be configured to report “out of family” batteries.

Abstract: A safety circuit includes a thermal fuse electrically connected in a main current path so that an electric current flowing in the main current path flows, through the thermal fuse; a switching element electrically connected to the thermal fuse to cause the thermal fuse to open and interrupt the electric current flowing in the main current path when the switching element is turned on; a microcontroller electrically connected to the switching element and the main current path to turn on the switching element when an overcurrent flows in the main current path; and a noise removing unit electrically connecting the microcontroller to the switching element.

Abstract: A circuit arrangement that has an energy source that can provide a charging voltage for charging an electrical energy storage unit in a charging circuit when it is connected to an energy supply, wherein it is possible to represent the charging voltage using an alternating quantity, and that has a capacitor circuit having a first capacitor element, a first valve element, and the energy source, wherein the first capacitor element is charged by the energy source via the first valve element if the charging voltage is negative, so that, if the charging voltage is positive, the voltage over the first capacitor element has the same orientation in the capacitor circuit, in terms of sign, as the charging voltage, and the voltage over the capacitor element.

Abstract: The remaining capacity of a power source, such as a battery, may be monitored with a microprocessor by integrating data received from a current sensor. The microprocessor may measure electrons passing through the battery by sampling the integrator and summing the values recorded from the integrator. Each time the integrator is sampled, the microprocessor may reset the integrator to prevent the integrator from saturating. The microprocessor may sample the integrator when the integrator approaches a predetermined value. The remaining capacity of the battery may be calculated based on calibration values and the sum of electrons measured by the integrator. The remaining capacity may be communicated to remote users through a network and displayed in an executive dashboard.

Abstract: A method for reducing leakage current generated by a pull-down circuit detects if leakage current is generated by the pull-down circuit and collects at least a portion of the leakage current. The collected leakage current is amplified and output to a battery. The apparatus to reduce leakage current includes a pull-down circuit to generate leakage current, a leakage current detector to detect the leakage current and to collect at least a portion of the leakage current, an integrator to receive leakage current and to amplify the leakage current; and a battery to receive voltage generated from the amplified leakage current.

Abstract: A battery charger and a battery charge method are provided. The battery charger and the battery charge method allow a battery to be charged in accordance with a charge algorithm optimum for the battery and based on a charge characteristic of the battery acquired at the time of daily charge of the battery. A battery charger includes battery charge means for charging a battery connected thereto based on a predetermined charge algorithm and signal analysis means for analyzing the battery based on a charge signal sent from the battery charge means, and the battery charge means automatically switches the charge algorithm to another in accordance with the state of the battery analyzed by the signal analysis means and repeats the charge a predetermined number of times.

Abstract: A method and system for controlling charging of a rechargeable battery to obtain a desired state of battery charge. In one embodiment the method comprises assessing an indicator of state of battery charge to determine current battery charge and determining the desired state of battery charge at a predetermined point in an expected battery load pattern. Then receiving an indication of an operational characteristic of an available charge source per time slot to charge the rechargeable battery until the predetermined point and calculating in which of the time slots to charge the battery in order to charge the rechargeable battery to the desired state of battery charge by the predetermined point in the expected battery load pattern to optimise a charging characteristic to the predetermined point. A device and computer program produce is also disclosed, to run continuously, subject to configured parameters, to optimise charging characteristics.

Abstract: Systems and methods are provided for monitoring the deterioration of a rechargeable battery. A battery monitoring system may be used to store charging information, discharge information and storage information for a rechargeable battery to a data store. The charging information may include a number of charge cycles incurred by the rechargeable battery. The discharge information may include a number discharge cycles incurred by the rechargeable battery. The storage information may include information relating to periods when the rechargeable battery is not being actively charged or discharged. The battery monitoring system may be further used to determine an amount of deterioration of a battery performance characteristic based on the stored charging information, discharge information and storage information.

Abstract: A by-pass circuit for a battery system that disconnects parallel connected cells or modules from a battery circuit or controls the current through the parallel connected cells or modules. If a cell has failed or is potentially failing in the system, then the by-pass circuit can disconnect the cell or module from other cells or modules electrically coupled in parallel. If a cell or module has a lower capability than another cell or module, then the by-pass circuit can control the current to the cell or module to maximize the performance of the system and prevent the system from creating a walk-home condition.

Abstract: A power delivery rate from a renewable power source to a load is managed by determining, by processing circuitry, a change in a power generation rate, determining, by the processing circuitry, whether the change in the power generation rate exceeds a limit, and then, adjusting, by control circuitry, a power transfer rate to or from a power storage device, such that the adjusting is sufficient to prevent the power delivery rate from exceeding the limit.

Abstract: Provided is a battery state monitoring circuit including: a charge/discharge control circuit for detecting and controlling a state of a secondary battery; an automatic recovery circuit; a temperature sensor circuit; and a comparator for comparing a voltage of an output terminal of the automatic recovery circuit and a voltage of the secondary battery, and outputting a signal indicative of a result of the comparison to the temperature sensor circuit, to control an operation of the temperature sensor circuit. The temperature sensor circuit operates only when the output of the automatic recovery circuit is larger, that is, only when a charger is connected between external terminals.

Abstract: A current sensor includes a magnetic balance sensor and a switching circuit. The magnetic balance sensor includes a feedback coil which is disposed near a magnetic sensor element varying in characteristics due to application of an induction field caused by measurement current and which produces a canceling magnetic field canceling the induction field. The switching circuit switches between magnetic proportional detection and magnetic balance detection. The magnetic proportional detection is configured to output a voltage difference as a sensor output. The magnetic balance detection is configured to output, as a sensor output, a value corresponding to current flowing through the feedback coil when a balanced state in which the induction field and the canceling magnetic field cancel each other out is reached after the feedback coil is energized by the voltage difference.

Abstract: The method includes the simultaneous measurement of the current I, of the positive plate potential V+, and of the temperature T at the positive terminal of the battery, the determination of a temperature compensated value Vc+ of the positive plate potential and the use of the temperature compensated value Vc+ for estimation of the state of charge. This method is more particularly used for estimation of the state of charge of an alkaline battery having a NiOOH positive plate.

Abstract: A flashlight includes a light powered by a battery, and a circuit having: a memory for storing a battery life information and voltage output information versus time for the battery to power the light, a controller operating a count down timer to accumulate an amount of time that the battery powers the light, a voltage measure circuit for monitoring the voltage output by the battery while the battery powers the light and supply the voltage output to the controller. The controller determines: a first remaining battery life by comparing the accumulated time to the battery life, a second remaining battery life by comparing the voltage output to the voltage output information, and the lesser of the first and second remaining battery lives. The flashlight includes a display for receiving a command from the controller to display the lesser of the first remaining battery life and the second remaining battery life.

Abstract: The electronic apparatus allows a user to arbitrarily set a display of a remaining battery level. The apparatus includes a detector which detects a remaining battery level of a battery, and a threshold-value-setting part which is operated by a user to set a threshold value for performing a display relating to the remaining battery level. The apparatus further includes a controller which displays in a display device an image representing the remaining battery level in accordance with the result of a comparison between the remaining battery level detected by the detector and the threshold value set with the threshold-value-setting part.

Abstract: A power booster includes a voltage detection circuit, a battery charger, a rechargeable battery, and a transformer circuit. The voltage detection circuit detects a voltage of the input voltage of the power booster. An input of the battery charger is electrically connected to an output of the voltage detection circuit. The rechargeable battery includes an I/O port electrically connected to the battery charger. The transformer circuit includes a first voltage input, a second voltage input, and a voltage output. The first voltage input is electrically connected to the output of the voltage detection circuit. The second voltage input is electrically connected to the I/O port. The voltage output is used for connecting to a mobile electronic device.

Abstract: In control of the disk array device (backup system), when a blackout occurs, the disk array device is first operated in a first method to backed up a main memory by using a power supply from a battery. During the first method, a blackout continuous time and the like are integrated, and at a timing in which the integrated value satisfies a condition, the first method is then shifted to the second method to evacuate data from the main memory onto a nonvolatile memory based on a power supply.

Abstract: An object of this invention is to simultaneously resolve a decline in capacity due to undercharging of, and degradation due to overcharging of, a lead-acid battery, which occur as a result of random charging. A method of controlling a lead-acid battery of this invention is characterized in that a first region extending until an accumulated discharged capacity D1 at which a theoretical discharged capacity is the maximum value Dmax is reached, and a subsequent second region in which the accumulated discharged capacity D1 is exceeded, are set, and in that a value R1 obtained by dividing an accumulated charged capacity C1 by the accumulated discharged capacity D1 in the first region is made to be larger than a value R2 obtained by dividing an accumulated charged capacity C2 by an accumulated discharged capacity D2 in the second region.

Abstract: A computer system includes a device which operates depending on a clock frequency; a battery unit which comprises a plurality of battery cells and supplies power to the device; a temperature sensor which senses temperature of the battery cells; and a controller which decreases the clock frequency if the sensed temperature is beyond a first preset critical point.

Abstract: A battery charging system for charging a battery with a plurality of battery cells. The battery charging system includes a battery charger and a battery management unit. The battery management unit includes a plurality of balancing circuits for controlling charging of each battery cell. The battery charging system can charge the battery in different stages depending on the voltage of each battery cell.

Abstract: A voltage detection circuit comprises a plurality of even-number voltage detection nodes, at least one odd-number voltage detection node, a voltage differential generation circuit, a selection circuit and a computing circuit. The selection circuit is for controlling the coupling relationship between the voltage differential generation circuit and the even and odd-number voltage detection nodes, so that the voltage differential generation circuit generates a voltage differential between the nodes. The computing circuit knows a voltage of a first even-number voltage detection node being as a reference voltage or obtains the voltage of the first even-number voltage detection node on the basis of the reference voltage, and respectively obtains a voltage of the nodes on the basis of the voltage differential between two adjacent nodes and the obtained voltage of a first even-number voltage detection node.

Abstract: Systems and methods of monitoring battery health in an HVAC system. The charge state of a rechargeable battery and the number of amp-hours provided to or from the rechargeable battery are monitored. The number of amp-hours provided is recorded and an end-of-life condition is detected based on the number of amp-hours provided during the charge or discharge cycle. In some constructions, the end-of-life condition is detected by comparing the number of amp-hours provided during the charge or discharge cycle to a threshold. In some constructions, the end-of-life condition is detected by calculating a rate of change of the number of amp-hours provided during a charge or discharge cycle and comparing the rate of change to a threshold.

Abstract: A method and system for determining standby time for a mobile station uses a battery simulator, a base station emulator, a computer to control the test equipment and MSUT for testing a mobile station. The computer includes a module for determining a radio off battery voltage, a module for deriving a battery capacity in dependence upon the radio off battery voltage, a module for measuring battery capacity usage in a predetermined time while the mobile station is in standby mode and a module for determining a standby time for the mobile station in dependence upon the battery capacity and the battery capacity usage, where the predetermined time is less than the standby time.

Abstract: Charging of a lithium ion secondary battery including a positive electrode including a positive electrode active material capable of absorbing and releasing lithium ions, a negative electrode including a negative electrode active material being an alloy-formable active material capable of absorbing and releasing lithium ions, a separator interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte is performed. In charging, the remaining capacity and the temperature of the lithium ion secondary battery are detected, and the lithium ion secondary battery is charged until the battery voltage reaches a reference voltage E1 associated beforehand with the remaining capacity and the temperature.

Abstract: A robotic charging station for charging a battery of an electric vehicle includes a base plate, a riser coupled with the base plate and extending substantially transverse to the base plate, and a robotic arm. The robotic arm extends from the riser and supports an end effector. The end effector includes a plurality of electrical contacts configured to couple with a receptacle disposed on the electric vehicle. The robotic arm is configured to move the end effector in three degrees of motion.

Abstract: A full charge capacity value correction circuit includes: a current detection portion which detects a current value in a secondary battery; a voltage detection portion which detects a terminal voltage value of the secondary battery; a capacity storage portion which stores a full charge capacity value of the secondary battery; a remaining quantity calculation portion which calculates a remaining charging quantity in the secondary battery a remaining quantity estimation portion which estimates a remaining quantity of the secondary battery and a full charge capacity value correction portion which, when an estimated remaining quantity becomes equal to a reference value set in advance, adds a difference electrical quantity, to the full charge capacity value stored in the capacity storage portion, or subtracts the difference electrical quantity from the full charge capacity value stored in the capacity storage portion based on an estimated remaining quantity and an accumulated remaining quantity.

Abstract: A battery unit includes: a battery having cell units connected in parallel, in which one or a plurality of battery cells is connected in series; an external terminal provided for the battery; a switching element provided between each internal terminal and the external terminal of the cell unit; a protection circuit monitoring whether or not a fault occurs in each of the plurality of cell units and cutting off, through the switching element, a connection between the internal terminal and the external terminal of the cell unit with the fault detected; and an informing signal output terminal notifying an external device that the connection with the external terminal with respect to at least one of the cell units is cut off.

Abstract: The present invention is directed to apparatuses, systems, methods, and computer readable media that can facilitate the transfer of power between at least two electrical devices. At least one of the electrical devices is preferably a battery operated device. The present invention may also be used to facilitate the transfer of information among electrical devices. For example, the present invention may be used to automatically pair two Bluetooth devices together.

Abstract: A vehicle includes a charging unit receiving electric power from an external power source and externally charging a power storage unit. When a connector unit is coupled to the vehicle and a state ready for charging by the external power source is attained, a controller predicts degradation ratio of the power storage unit at the time point of completion of external charging based on degradation characteristic of the power storage unit in connection with SOC and battery temperature obtained in advance, and sets target state of charge of each power storage unit based on the battery temperatures so that the predicted degradation ratio does not exceed tolerable degradation ratio at the time point of completion of external charging. Then, the controller controls corresponding converters such that SOCs of power storage units attain the target states of charge.

Abstract: The present disclosure provides a management device for a charging circuit and a wireless terminal, which belong to the technical field of management control of a linear charging circuit. The device includes a power supply management module (5), a buck switching voltage converter (1) and a linear charging circuit (2). The power supply management module (5) includes an adjustable Low Dropout (LDO) linear regulator (6) and an Analog-to-Digital Converter (ADC) (4), wherein the output terminal of the adjustable LDO linear regulator (6) is connected with the feedback terminal of the buck switching voltage converter (1) through a first preset resistor (R62). The input terminal of the ADC (4) is connected with the anode of a battery (3). The control terminal of the power supply management module (5) is connected with the control terminal of the linear charging circuit (2). The output terminal of the buck switching voltage converter (1) is connected with the input terminal of the linear charging circuit (2).

Abstract: A charging circuit for a battery includes an input terminal configured for providing a charging voltage, a switching unit connected between the input terminal and the battery, and a protection unit. The protection unit is configured for detecting a voltage of the battery and determining whether the voltage of the battery less than a predetermined voltage and controlling the switching unit to activate or terminate charging of the battery.

Abstract: A charging signal Vi responding to a charging current is inputted to one input terminal (?) of an operational amplifier 95 forming a comparator and a setting signal Vr corresponding to a setting current value is inputted to the other input terminal (+) of the operational amplifier 95. When the charging signal Vi is not higher than the setting signal Vr, a charging stop signal is generated from the output terminal of the operational amplifier 95 to interrupt a switch unit 4. A starting signal Vcc larger than the setting signal Vr applied to the other input terminal (+) is applied to the one input terminal (?) of the operational amplifier 95 through a condenser 94 till a prescribed time elapses from the start of a charging operation to generate a charging start signal from the output terminal of the operational amplifier 95 and electrically conduct the switch unit 4.

Abstract: Provided are a battery state monitoring circuit and a battery device which can be readily adapted to variation in number of batteries, and has low withstand voltage and a simple circuit configuration.

Abstract: Methods and systems for determining a state of charge of a battery exhibiting a transient response are provided. At least one property of the battery is measured. The state of charge of the battery is determined based on the at least one measured property and a transient response of the battery.

Abstract: In a hybrid electric motor vehicle , a power supply system for storing and supplying electrical power includes a motor-generator located onboard the vehicle, driveably connected to the vehicle wheels and producing AC electric power, an energy storage device for alternately storing and discharging electric power, an inverter coupled to the motor-generator and the energy storage device for converting alternating current produced by the motor-generator to direct current transmitted to the energy storage device, and for converting direct current stored in the energy storage device to alternating current transmitted to the motor-generator, an off board source of AC electric power located external to the vehicle, and a charger coupled to said electric power source and the energy storage device for supplying DC electric power to the energy storage device from said AC electric power source.

Abstract: An apparatus and a method stabilize a charging current when recharging a battery in a device that uses a rechargeable battery. The device includes a charge module and a controller. The charge module provides a charging current to the battery, and operates in at least one of a Constant Current (CC) mode that maintains the charging current at a fixed value while the battery is charged, and a Constant Voltage (CV) mode that maintains a battery voltage at a reference value. The controller controls the charge module to operate in the CC mode when starting charging, controls the charge module to operate in the CV mode when the battery voltage reaches the reference value, and controls the charge module to operate in the CC mode for at least one time duration after the battery voltage reaches the reference value.

Abstract: A method for improving the performance of a traction battery during a driving start phase of an electric vehicle. A driving start point in time at which the driving start phase begins is provided. A temperature of the traction battery is detected. This temperature is compared with a minimum operating temperature, and the traction battery is heated if the comparison reveals that the temperature of the traction battery is below the minimum operating temperature. The heating takes place with a temperature increase which provides a temperature of the traction battery at the driving start point in time, which is no lower than the minimum operating temperature.

Abstract: The car battery system of the present invention is provided with a battery block 2 that retains a plurality of battery cells 1 in a stacked configuration and has a terminal plane 2A, which is coincident with terminal surfaces 1A established by positive and negative battery cell 1 electrode terminals 13; and with a battery state detection circuit 30 that connects with the electrode terminals 13 of each battery cell 1. The battery system is provided with a circuit board 7 with surface-mounted electronic components 40 that implement the battery state detection circuit 30. The circuit board 7 is a single-sided board with electronic components 40 mounted on only one side, and the circuit board 7 is attached to the battery block 2 opposite the terminal plane 2A with the side having no electronic components 40 facing the battery block 2. The positive and negative electrode terminals 13 of each battery cell 1 are connected with the circuit board 7 for connection to the battery state detection circuit 30.

Abstract: Limit values of battery charging and discharging power are set by a battery charge discharge control apparatus, based on the estimation of the internal resistance of a battery according to a detected battery temperature and the sampling of a battery current and a battery voltage respectively detected by a current sensor and a voltage sensor. The limit values are used to control the battery current and the battery voltage to be within a current use range and a voltage use range of the battery, according to conditions of the battery in a vehicle.

Abstract: A battery management system (BMS) and a method of controlling the same are disclosed. In one embodiment, the BMS includes a reference setup unit configured to set a charge completion value used to calculate a state of health (SOH) of the battery, wherein the battery comprises one or more battery packs each including a plurality of battery cells, and a charge amount calculation unit configured to calculate an amount actually charged in the battery from a first point in time when charging of the battery begins to a second point in time when the battery charging actually reaches the charge completion value. The BMS may further include an SOH calculation unit configured to calculate the SOH of the battery based on a ratio of i) the actual charge amount to ii) a preset charge amount expected to be charged from the first time point to the second time point.

Abstract: When a battery current is not larger than a limit current set depending on the battery temperature and is flowing continuously for a predetermined time set depending on the battery temperature or longer, a decision is made that a secondary battery is in stable state. When the secondary battery is in stabilized state, the battery voltage is considered to be equal to the open circuit voltage and SOC estimation is performed based on the open circuit voltage-SOC characteristics. When the product of the internal resistance of the secondary battery and the limit current is made substantially constant (constant voltage) by setting the limit current in association with temperature dependence of the internal resistance, estimation error can be kept within a predetermined range in the stabilized state even if SOC estimation is performed while the battery voltage is assumed as the open circuit voltage.

Abstract: A method, circuit, and topology are provided for utilization of this circuit in Li-Ion or any other battery that benefits from balancing between individual cells. The whole system is characterized as having high efficiency (and thus low heat losses) compared to previous art implementations. The actions of the circuit are continuous and bi-directional in respect to each cell.

Abstract: The state monitoring apparatus includes a high-voltage side monitoring section having monitoring units assigned to respective unit batteries and a low-voltage side monitoring section having a control device. The monitoring units measures the voltages of the unit batteries upon reception of a voltage measurement command transmitted from the control device, and determines whether or not the measured voltages are within a predetermined range. This determination is transmitted to the control device. If this determination is negative, the control device limits a charge/discharge current of the assembled battery, and then causes the monitoring units to transmit the measured voltages.

Abstract: The amount of energy actually available in an energy storage module having a plurality of individual storage elements connected in series is determined. An upper and/or a lower limit voltage for the energy storage module is determined dynamically. During a charging operation of the energy storage module, in the event that a maximally permissible upper cell voltage is reached on at least one storage cell, the upper limit voltage of the energy storage module is determined by summing all cell voltages of all storage elements existing at that point-in-time. During a discharging operation, if a minimally permissible lower cell voltage is reached on at least one storage element, the lower limit voltage is determined by summing all cell voltages existing at that point-in-time. The actually available amount of energy is computed as a function of the determined limit voltage or voltages and of the determined actual storage capacity.

Abstract: Capacity degradation due to charge/discharge cycles is suppressed in either a non-aqueous electrolyte secondary cell provided with a positive electrode including, as a positive electrode active material, a lithium-transition metal complex oxide having a layered structure and containing at least Ni and Mn as transition metals, and a negative electrode containing a carbon material as a negative electrode active material and having a higher initial charge-discharge efficiency than that of the positive electrode, or an assembled battery having a plurality of cells each of which is the secondary cell. A control circuit incorporated in the secondary cell or the assembled battery, or in an apparatus using the secondary cell or the assembled battery, monitors the voltage of the secondary cell or each of the cells in the assembled battery so that the end-of-discharge voltage of each cell is 2.9 V or higher.