The University of Toledo

Daimlerchrysler Corporation

Chrysler Corporation

Other

Chrysler Group LLC

Thomas A Stuart

Cyrus N Ashtiani

Keming Chen

Zhong Ye

An equalizer circuit provides both passive and active cell voltage equalization in a battery pack to improve charge and discharge capacity at a low cost. The equalizer circuit is a bilevel circuit that uses both passive equalizers and active equalizers to balance cell voltage. The cells may be grouped into size limited sections which are balanced by passive equalizers. The sections are balanced by active equalizers to promote increased pack charge and discharge capacity. The equalizer circuit can use a current detector or a voltage controlled oscillator to assist in closed loop current control to reduce switching losses and permit use of smaller transistors. The equalizer circuit can use open line protection with capacitors to store excess charge and prevent voltage overload of the switching devices.

Bilevel equalizer for battery cell charge management

An equalizer circuit provides both passive and active charge transfer between cells in a battery pack to improve charge and discharge efficiency. The equalizer circuit is a bilevel circuit that uses both resistive equalizers and switching equalizers to balance cell charge. The cells may be grouped into size limited sections which are balanced by resistive equalizers. The sections are balanced by switching equalizers to promote increased pack discharge capacity.

An energy storage system for a vehicle includes an ultracapacitor that is electrically coupled in parallel with a battery through a diode connected in series with the battery. The ultracapacitor delivers the energy required for all high current surges that occur during engine start, acceleration, and regeneration. The battery is used only to assist with longer duration, high energy loads, such as accessory loads when an engine of the vehicle is not running. In other words, the battery conducts only during longer and less-frequent pulses and, therefore, does not have to withstand high-power pulses.

Energy storage system with ultracapacitor and switched battery

A circuit for charging a battery combined with a capacitor includes a power supply adapted to be connected to the capacitor, and the battery. The circuit includes an electronic switch connected to the power supply. The electronic switch is responsive to switch between a conducting state to allow current and a non-conducting state to prevent current flow. The circuit includes a control device connected to the switch and is operable to generate a control signal to continuously switch the electronic switch between the conducting and non-conducting states to charge the battery.

Circuit with a switch for charging a battery in a battery capacitor circuit

An apparatus connected to an energy storage device for powering an electric motor and optionally providing a warming function for the energy storage device is disclosed. The apparatus includes a circuit connected to the electric motor and the energy storage device for generating a current. The apparatus also includes a switching device operably associated with the circuit for selectively directing the current to one of the electric motor and the energy storage device.

Battery self-warming mechanism using the inverter and the battery main disconnect circuitry

An electronic circuit for measuring voltage signals in an energy storage device is disclosed. The circuit includes a plurality of battery segments forming the energy storage device. An amplifier circuit is connected across one of the battery segments for converting a differential voltage to a reference current. A sense resistor is associated with the amplifier circuit to convert the reference current to a voltage signal which is proportional to the voltage across the battery segment. A voltage measurement node associated with the sensing resistor may be used for measuring the voltage signal. In one embodiment of the invention, a multiplexing and sampling circuit provides digitized voltage samples to a processor. The voltage level of each cell within the battery pack can then be monitored by the processor.

Electronic circuit for measuring series connected electrochemical cell voltages

A circuit for heating energy storage devices such as batteries is provided. The circuit includes a pair of switches connected in a half-bridge configuration. Unidirectional current conduction devices are connected in parallel with each switch. A series resonant element for storing energy is connected from the energy storage device to the pair of switches. An energy storage device for intermediate storage of energy is connected in a loop with the series resonant element and one of the switches. The energy storage device which is being heated is connected in a loop with the series resonant element and the other switch. Energy from the heated energy storage device is transferred to the switched network and then recirculated back to the battery. The flow of energy through the battery causes internal power dissipation due to electrical to chemical conversion inefficiencies. The dissipated power causes the internal temperature of the battery to increase. Higher internal temperatures expand the cold temperature operating range and energy capacity utilization of the battery. As disclosed, either fixed frequency or variable frequency modulation schemes may be used to control the network.

Circulating current battery heater

An electronic circuit for measuring voltage signals in an energy storage device is disclosed. The electronic circuit includes a plurality of energy storage cells forming the energy storage device. A voltage divider circuit is connected to at least one of the energy storage cells. A current regulating circuit is provided for regulating the current through the voltage divider circuit. A voltage measurement node is associated with the voltage divider circuit for producing a voltage signal which is proportional to the voltage across the energy storage cell.

Electronic circuit for measuring series connected electrochemical cell

An energy management system for monitoring an energy storage device is disclosed. The energy management system includes a plurality of cells forming the energy storage device. Each of the cells includes a line for communicating a voltage signal. A local module is connected to the cells of the energy storage device. The local module has a plurality of inputs for receiving the voltage signals generated by the cells. The local module provides a multiplexed output signal. A processor is provided for receiving the multiplexed output signal from the local module and monitoring the voltage signals produced by the energy storage device.

Multiplexed modular battery management system for large battery packs

A circuit for heating an energy storage device is disclosed. The circuit includes a switching device having a closed state and an open state. The circuit also includes a storage circuit for storing energy. The storage circuit has a resonating frequency. A controller is provided for operating the switching device. In operation, energy is transferred from the energy storage device to the storage circuit while the switching device is in the open state, and returned from the storage circuit to the energy storage device while the switching device is in the closed state. This energy transfer causes warming of the energy storage device.

Efficient resonant self-heating battery electric circuit

An electronic battery equalization circuit that equalizes the voltages of a plurality of series connected batteries in a battery pack. The current waveform is in the shape of a ramp for providing zero current switching. The transformer has a primary winding circuit and at least one secondary winding circuit. In one embodiment, each secondary winding circuit is connected to a different pair of batteries. The equalizing current is provided to the lowest voltage batteries in one half of the battery pack during one half of the charging cycle. The equalizing current is then provided to the lowest voltage batteries in the other half of the battery pack during the other half of the charging cycle. In another embodiment, each secondary winding circuit is connected to a different single battery. The equalizing current is supplied to a lowest voltage battery in the battery pack during each half of the switching cycle. The electronic battery equalization circuit also includes a feedback control circuit coupled to the primary winding circuit for controlling the current from the equalizing current supply source. In another embodiment, optically coupled switches are connected to a battery voltage monitor to provide equalizing current to the lowest voltage even and odd numbered battery in the battery pack.

Battery equalization circuit with ramp converter and selective outputs

A battery charger control system and method for maximizing output power to a battery. This is achieved by ensuring operation at either the maximum allowable input current or the thermal limit imposed by the battery charger using an on-line controller. In the invention, the thermal limit is determined by the junction temperatures of the two main IGBT's. Because direct measurement of these temperatures is impractical, they must be calculated by a computer algorithm that uses various on-line measurements. Test results for a 8 kW battery charger indicate reduction in the bulk charging time from conventional battery chargers of about 26% when charging a set of NiFe batteries.

Battery charger control system

An electronic battery equalization circuit that equalizes the voltages of a plurality of series connected batteries in a battery pack. The current waveform is in the shape of a ramp for providing zero current switching. The ramp converter power circuit has at least one semiconductor device and a transformer coupled to the equalizing voltage supply source. The transformer has a primary winding circuit and at least one secondary winding circuit. In one embodiment, each secondary winding circuit is connected to a different pair of batteries. The equalizing current is provided to the lowest voltage batteries in one half of the battery pack during one half of the charging cycle. The equalizing current is then provided to the lowest voltage batteries in the other half of the battery pack during the other half of the charging cycle. In another embodiment, each secondary winding circuit is connected to a different single battery. The equalizing current is supplied to a lowest voltage battery in the battery pack during each half of the switching cycle. The electronic battery equalization circuit also includes a feedback control circuit coupled to the primary winding circuit for controlling the current from the equalizing current supply source.

Battery equalization circuit with ramp converter

A full bridge DC to DC converter which provides zero voltage switching (ZVS) for one leg of the bridge and zero current switching (ZCS) for the other leg of the bridge is described. ZVS is achieved with parallel capacitors, while ZCS is achieved by using the reverse breakdown characteristics of the various diode and switching devices. This technique provides a significant reduction in the switching losses of the switching devices, which allows for higher power and frequency combinations.

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Toledo, OH, United States of America

Thomas A Stuart