Abstract: A battery system is disclosed. The battery system includes a plurality of battery cells, and a battery cell balancing unit, configured to adjust voltages across each of the battery cells to reduce variation among the voltages across the battery cells. The battery cell balancing unit includes a controller configured to receive a DC reference current and to generate an AC current based on the DC reference current, a transformer, a rectifier circuit including a rectifier connected to the output coil, and a switching unit including a plurality of switches, each configured to selectively connect the rectifier to one of the battery cells.

Abstract: An electric power tool is included in a plurality of types of electric power tools. The plurality of types of electric power tools comprise a plurality of types of battery packs having different rated output voltages and a plurality of types of tool bodies, the housings of which are equipped with an attached part on which each of the battery packs is mounted in a freely removable manner. The attached part possessed by the plurality of types of tool bodies equipped with motors having different voltage characteristics is formed so as to be able to mount an arbitrary one of the plurality of types of battery packs having different rated output voltages. This makes it possible to widen the range of available battery packs and enhance convenience.

Abstract: Temperature characteristics of battery cells are detected. In accordance with one or more embodiments, an intercept frequency is detected for each battery cell, at which frequency an imaginary part of a plot of impedance values of the battery cell exhibits a zero crossing. The impedance values correspond to current injected into the cell. A temperature of the cell is determined based upon the detected intercept frequency for the cell and stored data that models operation of the cell. Various approaches are implemented with different types of circuits coupled to detect the impedance values of the respective cells.

Abstract: A method for charging an assembled battery including series circuits connected in parallel, each of the series circuits including series-connected lead storage batteries, using a single charger is provided. The method includes: a first step of obtaining a first index value, corresponding to a resistance value of a first series circuit with a correlative relationship, the first series circuit having a lowest resistance value; a second step of obtaining a second index value corresponding to a resistance value of a second series circuit with a correlative relationship, the second series circuit having a highest resistance value; a third step of performing normal charging, in which the assembled battery is charged with a first amount of charge corresponding to the first index value; and a fourth step of performing refresh charging, in which the assembled battery is charged with a second amount of charge corresponding to the second index value.

Abstract: A temperature is measured for each terminal of the battery unit. The magnitude and sign of a temperature differential is calculated from the temperatures. The temperature differential is then correlated to a deteriorating condition of the battery unit.

Abstract: A power management system and method are disclosed. The system can be a high availability power delivery system. The system can be GPS tracked. The system can have multiple batteries, multiple input power sources, and multiple loads. The system can switch between the multiple batteries and the power source to deliver power to the load. The system can ensure there will always be an input power source to power the load.

Abstract: The present invention relates to a battery management apparatus of a high voltage battery for a hybrid vehicle, in more detail, a battery management apparatus of a high voltage battery for a hybrid vehicle which includes: a plurality of battery packs including a plurality of unit cells; slave battery management modules measuring and monitoring temperature and voltage of the unit cells in the battery packs; temperature/voltage measurement wires connecting the unit cells with adjacent unit cells for the slave battery management modules to measure temperature and voltage between the unit cells and the adjacent unit cells; a master battery management module connected with the slave battery management modules; and communication wires connecting the modules.

Abstract: An embodiment of the invention provides a rechargeable battery module including a battery bank having serial connected battery units, a charging transistor providing a charging current to the battery bank, a balancing circuit for detecting and balancing voltage values of battery units and battery bank and a control chip. When a first voltage value of a first battery unit reaches a charge-off voltage, the control chip estimates a first unbalanced voltage difference between the first voltage and the minimal voltage among battery units. The control chip disables the charging transistor and estimates a second unbalanced voltage difference between voltages of the first battery unit and the battery unit having a minimal voltage. The control chip enables the balancing circuit to balance the first battery unit. When the voltage of the first battery is dropped by a calibration target, the charging transistor is enabled.

Abstract: A method and system for detecting a charging current supplied to a portable device through a USB charger. The method includes the steps of connecting a charging circuit to a portable device, allowing the portable device to draw charging current from the charging circuit, measuring the current drawn from the charging circuit, comparing the measured current with a threshold value, making one or more system level decisions regarding charging of the portable device if the detected charging current is below the threshold current.

Abstract: A method is provided for current-based detection of an electrical fault in an electrical network of a motor vehicle, the network having at least: one battery, one pulse-controlled inverter, one d.c. voltage converter, and an intermediate circuit associated with the pulse-controlled inverter. The method includes: detecting magnitudes of each a battery current, a d.c. voltage converter current, and an intermediate circuit current; comparing current magnitudes according to provided equations; and checking based on the comparison of whether a specifiable deviation has been exceeded. An alternative method for voltage-based detection of an electrical fault in an electrical network of a motor vehicle includes: detecting magnitudes of each a battery voltage, a d.c. voltage converter voltage, and an intermediate circuit voltage; comparing voltage magnitudes according to provided equations; and checking based on the comparison of whether a specifiable deviation has been exceeded.

Abstract: A most recent electrostatic capacitance value for a backup capacitor is measured periodically. Each time the most recent electrostatic capacitance value is measured, a charging voltage (a required charging voltage) that is required in order to cause a return operation of a valve from the setting opening at that time to an emergency opening/closing position (for example, the fully closed position) is calculated based on the electrostatic capacitance value that has been measured. If the required charging voltage that has been calculated is higher than the terminal voltage that has been detected, then a value for a charging current value is determined based on the actual degree of opening and the setting opening of the valve, and the backup capacitor is charged until the terminal voltage reaches the required charging voltage.

Abstract: A method and system for determining the temperature of cells in a battery pack, without using temperature sensors, by measuring the impedance of the cells and using the impedance to determine the temperature. An AC voltage signal is applied to the battery pack, and a time sample of voltage and current data is obtained. The voltage and current data is narrowed down to a simultaneous time window of interest, and a fast fourier transformation is performed on the windowed voltage and current data to identify voltage and current magnitudes at one or more specific frequencies. The voltage and current magnitudes are used to determine the impedance at the one or more frequencies. Finally, the impedance is used to determine the temperature of the cell or cells using a look-up table, where the impedance, the frequency, and a state of charge are used as input parameters for the look-up.

Abstract: Disclosed are an electric vehicle (EV), an EV charging stand, and a communication system therebetween, the EV including a charge control unit configured to detect a preparation state for charging a battery and output a resistance varying signal according to the detected state, and a resistor unit configured to vary a resistance value in response to the resistance varying signal, thus changing a voltage value of a state signal transmitted to the EV charging stand, and the EV charging stand including a comparator configured to receive a stage signal from the EV, compare a voltage value of the received state signal with a reference value, and output a signal in response to a result of comparing, and a control unit configured to receive the signal from the comparator and detect a preparation state for charging the battery of the EV.

Abstract: The method for charging or discharging a battery comprises measurement of the voltage at the terminals of the battery and comparison of the measured voltage with an end of charging or discharging voltage threshold. The method also comprises measurement of a temperature representative of the temperature of the battery and measurement of the current flowing in the battery to form a pair of measurements. The voltage threshold is then determined according to the pair of measurements. Charging or discharging of the battery is stopped when the voltage threshold is reached.

Abstract: A battery management system and method accurately estimate a state of charge (SOC) of a battery. For this, the battery management system may include a unit SOC calculator calculating a unit SOC by using a charge/discharge current of a battery, an electromotive force SOC calculator calculating an electromotive force SOC using an electromotive force of the battery; a corrector calculating a compensation amount using the electromotive force SOC and a previous SOC, and an SOC calculator calculating a current SOC using the unit SOC, the previous SOC, and the compensation amount.

Abstract: The present invention provides a small fuel cell system including a secondary battery, in which deterioration in the secondary battery is suppressed regardless of a temperature condition. A control unit adjusts the supply amount of a liquid fluid of a fuel pump so that charging current I2 to a secondary battery becomes smaller than a predetermined maximum charging current value Imax. Consequently, for example, even in the case of using a small secondary battery, the charging current I2 is limited to be smaller than a predetermined upper limit value (maximum charging current value Imax). In addition, a temperature detecting unit detects temperature T1 of the secondary battery and the control unit controls the maximum charging current value Imax in accordance with the detected temperature T1 of the secondary battery. In such a manner, the operation of limiting the charging current I2 in accordance with the temperature T1 of the secondary battery at that time is performed.

Abstract: The present disclosure describes an apparatus and method for estimating state of health (SOH) of a battery. The apparatus for estimating state of health of a battery includes a sensing unit for measuring a battery voltage and current within a predetermined charging voltage range; a memory unit storing the battery voltage and current values measured by the sensing unit and SOH-based ampere counting values, obtained by an ampere counting experiment of a battery whose actual degradation degree is known; and a control unit for calculating an ampere counting value by counting the measured current values stored in the memory unit within the charging voltage range, and estimating a SOH value by mapping the SOH value corresponding to the calculated ampere counting value from the SOH-based ampere counting values stored in the memory unit.

Abstract: A load management system provides an interface between a power input and several switched power outputs and un-switched power outputs. A controller groups the switched power outputs into one or more load groups based on a switched current limit determined for the system and the measured currents of the electrical loads. The load groups are defined so that the sum of electrical load currents in each load group does not exceed the switched current limit. The controller also activates one or more switches to apply electrical power to the load groups according to a power sequence. A method for distributing electrical power to electrical loads using load groups is also provided.

Abstract: One embodiment includes a computer (102) controlled machine used in battery manufacturing and/or testing which discharges one or more batteries and uses some or all of the energy from said batteries to simultaneously charge one or more other batteries.

Abstract: A battery module for a portable electronic device is disclosed. The battery module is connected with the portable electronic device with at least three contacts. The battery module includes a battery, a recognition circuit, and a thermal sensing circuit. The recognition circuit has an energy storage element and a current limiting element, and the thermal sensing circuit has a switch and a thermal sensing element. The thermal sensing element varies its electric parameter in accordance with the temperature of the battery module. With the charging curve of charging the energy storage element by way of the current limiting element, the portable electronic device can determine a battery type, and the thermal sensing circuit is then initiated to acquire the thermal information of the battery module.

Abstract: Provided are an apparatus and a method for diagnosing an abnormality in a cell balancing circuit. The apparatus may include a plurality of cell balancing circuits respectively connected to a plurality of battery cells included in a battery pack for balancing the voltages of the battery cells, a diagnosis resistor respectively installed between the cell balancing circuit and a cathode terminal and an anode terminal of the corresponding battery cell, a voltage measuring unit for measuring a voltage difference of the balancing circuit corresponding to each of the battery cells, and a control unit for turning on or off a cell balancing circuit to be diagnosed and for determining whether there is an abnormality in the cell balancing circuit to be diagnosed, based on a variation pattern of a voltage difference of a cell balancing circuit adjacent to the cell balancing circuit to be diagnosed that is measured by the voltage measuring unit.

Abstract: Described are systems and methods for accurately characterizing thermodynamic and materials properties of electrodes and battery systems and for characterizing the state of health of electrodes and battery systems. Measurement of physical attributes of electrodes and batteries corresponding to thermodynamically stabilized electrode conditions permit determination of thermodynamic parameters, including state functions such as the Gibbs free energy, enthalpy and entropy of electrode/electrochemical cell reactions, that enable prediction of important performance attributes of electrode materials and battery systems, such as energy, power density, current rate, cycle life and state of health. Also provided are systems and methods for charging a battery according to its state of health.

Abstract: A method for protecting a battery cell from high-temperature swelling, the method includes: sensing a temperature and a voltage of the battery cell; determining whether the sensed temperature of the battery cell exceeds a reference temperature; determining whether the sensed voltage of the battery cell exceeds a reference voltage, when the sensed temperature of the battery cell exceeds the reference temperature; and self-discharging the battery cell in a charge/discharge/standby mode when the sensed voltage of the battery cell exceeds the reference voltage.

Abstract: Provided are a refresh charging method and a refresh charging apparatus for an assembled battery constituted from lead-acid storage batteries, by which a necessary charging rate may be performed while shortening a charging period. In a constant voltage charging mode, n intermediate threshold values S1 to Sn which decrease stepwisely are set between a predetermined threshold value S0 and a lower-limit current value, and n additional timer periods T1 to Tn are set where n is an integer equal to or larger than one. Counting of the n additional timer periods T1 to Tn is respectively started when the charging current reaches the n intermediate threshold values S1 to Sn. A maximum timer period Tm and the n additional timer periods T1 to Tn are set to satisfy a relationship of Tm>T1> . . . >Tn. Charging is stopped when the counting of one of the maximum timer period Tm and the n additional timer periods T1 to Tn is completed before the lower-limit current value is detected.

Abstract: A battery state-of-charge (SOC) estimator uses a robust H? filter design by taking into account the battery parameter uncertainties, which is due to battery age, variation, and operating conditions such as temperature and SOC level. Each of the time-varying battery parameter values and their variation rates are bounded. By utilizing the parameter variation bounds and parameter variation rate bounds into the design process and minimizing the H? gain from the measured current signal to the estimation error of Voc, the battery SOC estimator can achieve enhanced robustness to the variations of battery age, variation, and operating conditions that include temperature and SOC level.

Abstract: A battery voltage monitoring circuit includes a first power supply terminal to be connected to the positive terminal of a battery pack having rechargeable cells connected in series; a first supply voltage sensing terminal to be connected to the positive terminal of the battery pack; a first resistor connected between the first power supply terminal and the first supply voltage sensing terminal; a second supply voltage sensing terminal to be connected to the negative terminal of a first rechargeable cell of the rechargeable cells, the first rechargeable cell being on the positive terminal side of the battery pack and connected to the positive terminal of the battery pack; a second resistor connected between the second supply voltage sensing terminal and the first power supply terminal; and a first comparator configured to compare a voltage at the first power supply terminal and a voltage at the first supply voltage sensing terminal.

Abstract: A system and method of controlling a low-voltage DC/DC converter for an electric vehicle that include a battery sensor that senses information regarding a low-voltage battery during a stop of the electric vehicle for each first period when the electric vehicle stops and a controller that operates a low-voltage DC/DC converter to charge the low-voltage battery for a predefined time when an error occurs in the battery sensor. In addition, the controller determines a charge time of the low-voltage battery based on first SOC values of the information regarding the low-voltage battery sensed for each first period when no error in the battery sensor is detected and operates the low-voltage DC/DC converter for the determined charge time to charge the low-voltage battery.

Abstract: A charging control circuit for a secondary battery includes a temperature detection terminal for detecting the temperature of a secondary battery from an input detected voltage; a temperature comparison part having four threshold voltages corresponding to four reference temperatures, the temperature comparison part being configured to compare the four threshold voltages with the detected voltage input to the temperature detection terminal and to output a temperature range signal indicating the temperature range of the detected voltage; and a control part configured to control a charging current and/or a charging voltage based on the temperature range signal output from the temperature comparison part.

Abstract: A method and system for programming rechargeable battery characteristics is provided. The system having: a memory component for storing user profiles; a power management integrated circuit; and a processor for retrieving the user profiles and directing power from the battery to the power management integrated circuit in accordance with the user profiles. The method consists of: determining the type of battery; retrieving user profiles stored in a memory component; and adjusting the battery characteristics according to the user profiles.

Abstract: A method includes detecting that a battery pack requires charging and is currently operable for recharging. The method can identify a specific cell having a highest voltage in response to the detecting. The method can then recharge each cell of the battery pack to a predetermined voltage that is a sum of (i) a maximum open circuit voltage of the specific cell and (ii) a voltage based on a resistance of and a first current supplied to the specific cell. When a temperature of the specific cell is less than a predetermined temperature or an age of the specific cell is greater than a predetermined age, the method includes recharging each cell to the predetermined voltage at less than the first current when (i) a predetermined period has elapsed or (ii) a voltage of the specific cell is less than a voltage threshold.

Abstract: A system and method for charging batteries. Stops are adjusted for each of the batteries to secure the number of batteries in place. The batteries are placed to abut the stops. Adjustable contacts of the battery charger are positioned against terminals of the batteries. The batteries are secured within the receptacles of the battery charger. The batteries are charged.

Abstract: Systems and methods are provided for initiating a charging system. The method, for example, may include, but is not limited to, providing, by the charging system, an incrementally increasing voltage to a battery up to a first predetermined threshold while the energy conversion module has a zero-percent duty cycle, providing, by the charging system, an incrementally increasing voltage to the battery from an initial voltage level of the battery up to a peak voltage of a voltage source while the energy conversion module has a zero-percent duty cycle, and providing, by the charging system, an incrementally increasing voltage to the battery by incrementally increasing the duty cycle of the energy conversion module.

Abstract: A combined system reinforces the safety of lithium ion batteries by redesign of electrolyte and the charging current a) modifying the electrolyte to inhibit or prevent dendrite growth preferably by the addition of lithiated polyphenoxy polyethylene glycol and/or a second surface active compound chosen from the family of fluorosurfactants, and/or a modest amount of lithium or sodium borate, b) modifying the charging cycle by a so-called ripple current in order to inhibit or prevent dendrite growth (ripple current meaning oscillation in the amount of amperage or voltage in the charging cycle), c) programmable battery management systems with temperature and electrical limits integrated in order to eliminate from the circuit and bypass malfunctioning cells based on past performance of the charging cycle and voltage endpoints achieved, d) minimizing any transient currents and voltages into or out of the battery system and e) maintaining a cool atmosphere in the battery space.

Abstract: Some embodiments of the present invention provide a system that charges a battery. During operation, the system obtains a set of charging currents {I1, . . . , In} and a set of charging voltages {V1, . . . , Vn}. Next, the system repeats constant-current and constant-voltage charging operations, starting with i=1 and incrementing i with every repetition, until a termination condition is reached. These constant-current and constant-voltage charging operations involve charging the battery using a constant current Ii until a cell voltage of the battery reaches Vi, and then charging the battery using a constant voltage Vi until a charging current is less than or equal to Ii+1.

Abstract: A lithium polymer (LiPo) battery pack having LiPo battery cells is provided which includes battery protection circuitry, charging circuitry, cell balancing circuitry, and control and communication circuitry. The batteries can be charged while in use by an internal charger. Battery charging and discharging are accomplished in a controlled and protected manner to avoid overcharging and overdischarging conditions. The novel battery pack has built-in safeguards against dangerous LiPo battery conditions and is implemented in a small, portable unit which contains the battery cells, control and protection circuitry, internal charger and display gauge. The battery pack is useful for powering an intravenous fluid warmer or other medical or electrical devices and equipment.

Abstract: Method and circuits for sensing a bidirectional current without requiring an external sense resistor are disclosed. In a preferred embodiment the invention is applied for fuel gauging of one or more batteries and comprises a charger/active diode, which can source current into the battery and sink current from the battery to supply a mobile electronic device. The invention can be applied to any other application requiring sensing of bidirectional currents. A regulated cascode forces a voltage drop over a power transistor and a sense transistor to be the same. A feedback current is measured by an ADC. The integration of these current measurements over time is equal to the actual charge of the battery.

Abstract: Disclosed is a distributed battery management system that uses cell modules that are attached to cell terminals. A connector tab extends from the cell modules that provides a solid thermal and electrical connection to a cell terminal, as well as structural support for the cell module. A single wire is used to connect the cell modules that carries power, a voltage sample level, a serial data stream, indicating the temperature at a cell terminal to which the cell module is connected, and voltage level of each of the cells, as well as discharge current to equalize the charge of each of the cells. Various adapters can be used for different cell formats, which provide structural support for the cell modules. Reverse connection protection circuitry is also provided that protects the circuitry in the cell modules from accidental reverse connection.

Abstract: There is provided a method of thermally controlling an electric storage device. The method comprises increasing cooling medium supplied to the electric storage as an electric charge stored in the electric storage device increases. According to the method, by increasing the cooling medium supplied to the electric storage device as an electric charge stored in the electric storage device increases, the electric storage device may be kept at a temperature that increases the efficiency of charging or discharging the electric storage device. It is asserted to be more efficient to lower the temperature of the electric storage device when more electric charge is stored in the electric storage device. Also, an adequate amount of the cooling medium may be supplied to the electric storage. As a result, the overall efficiency of the electric system may be improved.

Abstract: The present invention relates generally to a method and apparatus for the management of individual cells in a battery system. More particularly, the present invention relates to the control of charging a battery system such that the cells stay balanced and the ability to produce a battery system profile and cell profile to adapt to the changes of the cells within the battery system.

Abstract: A mobile device adapted for dynamic power management. The mobile device includes an output power port, a voltage converter adapted to convert an input voltage to provide an output voltage to the output power port, and a processor. The processor is adapted to monitor at least one load electrically to determine when the at least one load will become active or inactive, determine a minimum required output voltage to be provided by the voltage converter based on the at least one load that will become active or inactive, control the voltage converter to provide at least the minimum required output voltage on the output power port in advance of the at least one load becoming active or after the at least one load becomes inactive, and when the input voltage is below the first threshold, control the voltage converter to reduce the output voltage.

Abstract: Systems and methods are provided for initiating a charging system. The method, for example, may include, but is not limited to, providing, by the charging system, an incrementally increasing voltage to a battery up to a first predetermined threshold while the energy conversion module has a zero-percent duty cycle, providing, by the charging system, an incrementally increasing voltage to the battery from an initial voltage level of the battery up to a peak voltage of a voltage source while the energy conversion module has a zero-percent duty cycle, and providing, by the charging system, an incrementally increasing voltage to the battery by incrementally increasing the duty cycle of the energy conversion module.

Abstract: An accumulator control device includes a first electrical connection configured to connect the accumulator control device to a local accumulator. A second electrical connection is connected to the first electrical connection and configured to connect to a remote auxiliary electrical power supply device. A control unit is configured to measure at least one of a parameter of the accumulator and an environmental parameter and to transmit at least one of the at least one measured parameter and a value calculated using the at least one measured parameter to the remote auxiliary electrical power supply device via a communication interface.

Abstract: A rechargeable battery pack is discontinuously charged in multiple discrete charging intervals. Reductions in battery pack voltage that occur during non-charging intervals, each transpiring between a respective pair of the discrete charging intervals, are measured. Multiple resistance values that characterize the internal resistance (DC resistance) of the battery pack are generated based on the reductions in battery pack voltage that occur during the non-charging intervals.

Abstract: It is an object to provide a battery system whose life can be extended. A cell pack having at least one lithium secondary battery that uses a manganese-based cathode material and a control unit that controls charging and discharging of the cell pack are provided, and the control unit controls charging and discharging within a low-degradation voltage range that is set on the basis of a target cell degradation rate.

Abstract: DC offsets introduced in battery testing equipment are automatically compensated for using complementary current-mode servo feedback. An op amp receives and amplifies a response signal, while also introducing internal errors manifested in the amplified response signal. A correction circuitry coupled to receive the amplified response signal and comprising a balanced circuit with a positive input correction device and a negative input correction device to remove the DC bias. The correction circuitry further comprises an error sensing device to correct for the internal errors introduced by the op amp.

Abstract: A battery pack includes a current control device that has a thermostat and a positive temperature coefficient device whose resistance increases as the temperature rises connected in parallel, the current control device being inserted into a discharge current path of a battery cell and a protection circuit that detects a voltage of the battery cell, detects an overcharge and over-discharge of the battery cell, and generates an overcharge detection signal and an over-discharge detection signal. In a normal state, a discharge current of the battery cell flows through the thermostat of the current control device. When the discharge current is large enough to damage the battery cell, the thermostat turns off and the discharge current flows through the positive temperature coefficient device. When the positive temperature coefficient device produces heat, a resistance of the positive temperature coefficient device increases and the discharge current is limited or interrupted.

Abstract: A controller 43 turns on a semiconductor switch 41 in a normal mode, and turns off the semiconductor switch 41 in a sleep mode. A bypass resistor 5 is connected in parallel to the semiconductor switch 41. A resistance value of the bypass resister 5 is so large as that in the sleep mode, a dark current is supplied to an electronic device 3 via the bypass resistor 5, and if an electric wire downstream of the bypass resistor is short-circuited, an electric current more than a permissive current is prevented from flowing to the electric wire.

Abstract: A system and method for scalable configuration of intelligent energy storage packs are disclosed. According to one embodiment, a method comprises providing a first current measurement of a first energy storage cell electrically connected to a first converter circuit, and the first converter circuit controls the charge and discharge of the first energy storage cell. A first voltage measurement of the first energy storage cell is provided. First control signals are received and the first control signals are determined according to a load policy. The first converter circuit transforms a first voltage from the first energy storage cell to a desired first bus contribution voltage according to the first control signals.

Abstract: A system (300) and method (400) for wireless charging are provided. A control circuit (304) charges one or more cells (301) in a secondary wireless charging circuit (308) that receives power wirelessly from a primary (312). The control circuit determines the state of charge and temperature of the cells. The control circuit then calculates a current limit as a function of a combination of the state of charge, input voltage to the control circuit for the wireless controller, FET power dissipation and the temperature and adjusts a wireless power control device (305) in the secondary such that its current limit is set to the state of charge current limit. Different temperature limits can be used for different states of charge such that the cells can be charged at higher temperatures at low states of charge than at higher states of charge.

Abstract: A battery cell measurement system comprising a signal generator coupled to a pulse density modulation circuit generating a control signal which drives a switch connected between a first terminal of a battery cell and a first terminal of a bleeding impedance, a second terminal of the bleeding impedance being coupled to a second battery cell terminal. The first terminal is coupled to a first terminal of a second switch. The second terminal is coupled to a first terminal of a third switch. A second terminal of the second switch and second terminal of the third switch are coupled and are further coupled to a low-pass filter. A signal generated by the low-pass filter is inputted into an analog to digital converter, which provides a signal representative of either a signal across the bleeding impedance, or a signal between the battery cell terminals.