US 2010/0244781 A1 · CELL MANAGEMENT SYSTEM

Abstract

A cell management system and method for balancing energy across a plurality of cells coupled to a circuit bus. The system can include a transformer, two transformer switches, and for each cell, a first switch pair allowing transfer of energy between the transformer and the cell, and a second switch pair allowing removal or inclusion of the cell in the serial connection of cells. The system can include an energy storage device, a switch pair allowing transfer of energy between the transformer and the storage device, and for each cell, a third switch pair allowing transfer of energy between the storage device and the cell. The system can include cell, bus and storage device sensors and state estimators. The system can include a controller that controls the transformer switches, cell switches, and storage device switches based on the sensor readings and states.

Claims22

Dependent claims

A cell management system for balancing energy across a plurality of cells coupled to a circuit bus, each cell of the plurality of cells including a positive terminal and a negative terminal, the cell management system comprising:

a transformer coupling the circuit bus and the plurality of cells, the transformer comprising a first inductor and a second inductor, the first inductor being coupled to the circuit bus and the second inductor being coupled to the plurality of cells;
a first transformer switch between the first inductor and the circuit bus;
a second transformer switch between the second inductor and the plurality of cells;
for each individual cell of the plurality of cells, a first cell switch pair and a second cell switch pair, the first cell switch pair of the individual cell allowing the transfer of energy between the transformer and the individual cell, and the second cell switch pair of the individual cell allowing the removal or inclusion of the individual cell in the serial connection of the plurality of cells;
a connection between the circuit bus and a first cell in the serial connection of the plurality of cells, the first cell being one of the plurality of cells and being located at a first end of the serial connection of the plurality of cells;
and
a connection between the circuit bus and a last cell in the serial connection of the plurality of cells, the last cell being one of the plurality of cells and being located at a second end of the serial connection of the plurality of cells, the second end being opposite of the first end.

4 more elements

for each cell of the plurality of cells, a first cell switch pair, a second cell switch pair, and a fourth cell switch pair;
a transformer comprising a first inductor and a second inductor, the first inductor being on a first side of the transformer and the second inductor being on a second side of the transformer;
the first cell switch pair for each cell of the plurality of cells being on the second side of the transformer, and the fourth cell switch pair for each cell of the plurality of cells being on the first side of the transformer;
a first transformer switch between the first inductor and the fourth cell switch pair for each cell of the plurality of cells;
a second transformer switch between the second inductor and the first cell switch pair for each cell of the plurality of cells;
a connection between the circuit bus and a first cell in the serial connection of the plurality of cells, the first cell being one of the plurality of cells and being located at a first end of the serial connection of the plurality of cells;
and
a connection between the circuit bus and a last cell in the serial connection of the plurality of cells, the last cell being one of the plurality of cells and being located at a second end of the serial connection of the plurality of cells, the second end being opposite of the first end.
wherein for each individual cell of the plurality of cells, the first cell switch pair of the individual cell allows the transfer of energy between the transformer and the individual cell, the second cell switch pair of the individual cell allows the removal or inclusion of the individual cell in the serial connection of the plurality of cells, and the fourth cell switch pair of the individual cell allows the transfer of energy between the transformer and the individual cell.

6 more elements

A method for controlling a plurality of cells connected to a transformer through a first set of switches to charge and discharge the transformer and connected in series through a second set of switches to provide energy to a system, the method comprising:

determining a state of charge value for each cell of the plurality of cells;
determining a minimum state of charge value for the plurality of cells;
determining a minimum state of charge cell having the minimum state of charge value for the plurality of cells;
determining a maximum state of charge value for the plurality of cells;
determining a maximum state of charge cell having the maximum state of charge value for the plurality of cells;
calculating a state of charge difference as the difference between the maximum state of charge value and the minimum state of charge value;
when the state of charge difference exceeds a state of charge deadband, equalizing the state of charge values of the plurality of cells using the transformer;
identifying whether any cells of the plurality of cells is unhealthy;
and
when an unhealthy cell is identified, bypassing the unhealthy cell.

7 more elements

determining a state of charge value for each healthy cell of the plurality of cells;
determining a minimum state of charge value across all of the healthy cells of the plurality of cells;
determining a maximum state of charge value across all of the healthy cells of the plurality of cells;
computing an average state of charge value for all of the healthy cells of the plurality of cells;
computing a delta minimum state of charge value equal to the difference between the average state of charge value and the minimum state of charge value;
computing a delta maximum state of charge value equal to the difference between the maximum state of charge value and the average state of charge value;
identifying any overcharged cells, an overcharged cell being any of the healthy cells of the plurality of cells that is overcharged;
identifying any undercharged cells, an undercharged cell being any of the healthy cells of the plurality of cells that is undercharged;
determining whether to equalize the state of charge values of the healthy cells of the plurality of cells;
identifying whether any cells of the plurality of cells is unhealthy;
and
when an unhealthy cell is identified, bypassing the unhealthy cell.

9 more elements

Dependencies are inferred from the claim text.

Cell management system

Life of this patent

Cell management system

Life of this patent

Abstract

Claims22