Cell balancing module and method in voltage balancing device for a stack of batteries which compares the cell voltages to a coded reference voltage derived from at least two reference voltages
First Claim
1. At least one cell balancing module for voltage balancing of a plurality of stacks of energy storage cells, comprising:
- an interface to input a coded reference voltage derived from at least two reference voltages, wherein each cell balancing modules is arranged to locally generate a local reference voltage from the coded reference voltageinput nodes for connecting at least one of the stacks of energy storage cells;
a switching unit connected to each of the input nodes; and
at least one local balancing unit which is coupled to the switching unit and to the interface and which is designed to compare the local reference voltage with cell voltages of the at least one of the stacks of energy storage cells to be connected, and designed to charge balance by charging or discharging the at least one of the stacks of energy storage cells to be connected depending on the comparison of the local reference voltage and the cell voltages,wherein the coded reference voltage is a digital representation of a reference voltage derived from a total system voltage of the plurality of stacks of energy storage cells,wherein the interface is a serial interface, and the coded reference voltage is simultaneously sent, as a digital representation, to the at least one local balancing unit via the serial interface,wherein a number of n cell balancing modules are inter-connected by way of a daisy chain via their respective interfaces,wherein local generation involves digital-to-analog conversion and the charge balance depends on an analog comparison between the local reference voltage and the cell voltages, andwherein each cell balancing module is arranged to acknowledge reception of the coded reference voltage by redundancy check.
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Accused Products
Abstract
The invention relates to a cell balancing module, particularly for voltage balancing of a stack of batteries. The cell balancing module comprises an interface (SPI, VrefH, VrefL) to input a coded reference voltage (Vref) and input nodes (In1, . . . , InN) for connecting a stack of energy storage cells (BAT1, . . . , BATn). A switching unit (SW) is connected to each of the input nodes (In1, . . . , InN) and a local balancing unit (loc) coupled to the switching unit (SW) and the interface (SPI, VrefH, VrefL). The local balancing unit (loc) is designed to compare the coded reference voltage (Vref) with cell voltages (VBAT1, . . . , VBATn) of the stack of energy storage cells (BAT1, . . . , BATn) to be connected and to charge balance the stack of energy storage cells (BAT1, . . . , BATn) to be connected depending on the comparison of coded reference voltage (Vref) and cell voltages (VBAT1, . . . , VBATn). The invention also relates to a voltage balancing device and method for cell balancing, particularly for voltage balancing of a stack of batteries.
70 Citations
21 Claims
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1. At least one cell balancing module for voltage balancing of a plurality of stacks of energy storage cells, comprising:
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an interface to input a coded reference voltage derived from at least two reference voltages, wherein each cell balancing modules is arranged to locally generate a local reference voltage from the coded reference voltage input nodes for connecting at least one of the stacks of energy storage cells; a switching unit connected to each of the input nodes; and at least one local balancing unit which is coupled to the switching unit and to the interface and which is designed to compare the local reference voltage with cell voltages of the at least one of the stacks of energy storage cells to be connected, and designed to charge balance by charging or discharging the at least one of the stacks of energy storage cells to be connected depending on the comparison of the local reference voltage and the cell voltages, wherein the coded reference voltage is a digital representation of a reference voltage derived from a total system voltage of the plurality of stacks of energy storage cells, wherein the interface is a serial interface, and the coded reference voltage is simultaneously sent, as a digital representation, to the at least one local balancing unit via the serial interface, wherein a number of n cell balancing modules are inter-connected by way of a daisy chain via their respective interfaces, wherein local generation involves digital-to-analog conversion and the charge balance depends on an analog comparison between the local reference voltage and the cell voltages, and wherein each cell balancing module is arranged to acknowledge reception of the coded reference voltage by redundancy check. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for voltage balancing for voltage balancing of a plurality of stacks of energy storage cells, comprising:
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encoding a coded reference voltage from at least two reference voltages, wherein each cell balancing modules is arranged to locally generate a local reference voltage from the coded reference voltage transmitting the coded reference voltage to at least one cell balancing module connected to at least one of the stacks of energy storage cells; comparing respective cell voltages of at least one of the stacks of energy storage cells at the at least one cell balancing module to the local reference voltage; and charge balancing by charging or discharging such that the respective cell voltages are adjusted depending on the comparison between the respective stack voltages and the local reference voltage, wherein the coded reference voltage is a digital representation of a reference voltage derived from a total system voltage of the plurality of stacks of energy storage cells, wherein the coded reference voltage is simultaneously sent, as a digital representation, to the at least one cell balancing module via a serial interface, and wherein a number of n cell balancing modules are inter-connected by way of a daisy chain via their respective interfaces, wherein local generation involves digital-to-analog conversion and the charge balance depends on an analog comparison between the local reference voltage and the cell voltages, and wherein each cell balancing module is arranged to acknowledge reception of the coded reference voltage by redundancy check. - View Dependent Claims (19)
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20. At least one cell balancing module for voltage balancing of a plurality of stacks of energy storage cells, comprising:
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an interface to input a coded reference voltage derived from at least two reference voltages, wherein each cell balances modules is arranged to locally generate a local reference voltage from the coded reference voltage input nodes for connecting at least one of the stacks of energy storage cells; a switching unit connected to each of the input nodes; and at least one local balancing unit which is coupled to the switching unit and to the interface and which is designed to compare the local reference voltage with cell voltages of the at least one of the stacks of energy storage cells to be connected, and designed to charge balance by charging or discharging the at least one of the stacks of energy storage cells to be connected depending on the comparison of the local reference voltage and the cell voltages, wherein the coded reference voltage is a digital representation of a reference voltage derived from a total system voltage of the plurality of stacks of energy storage cells, wherein the interface is a serial interface, and the coded reference voltage is simultaneously sent, as a digital representation, to the at least one local balancing unit via the serial interface, wherein a number of n cell balancing modules are inter-connected by way of a daisy chain via their respective interfaces, wherein local generation involves analog-to-digital conversion and the charge balance depends on a digital comparison between the local reference voltage and the cell voltages, and wherein each cell balancing module is arranged to acknowledge reception of the coded reference voltage by redundancy check. - View Dependent Claims (21)
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Specification