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US 9,755,451 B2Granted
Battery with autonomous cell balancing
AssigneesRobert Bosch GmbH, Samsung SDI Co., Ltd.
InventorStefan Butzmann
Life of this patent
Estimating the term…
Abstract
The disclosure relates to a device for balancing the battery cells of a battery including a plurality of pairs of battery cells. Each pair of battery cells is connected to a charge balancing unit which is configured to balance the cell voltages of the battery cells of the pair of battery cells with respect to each other. The device further includes a measuring device which is configured to output a current that is proportional to a minimal cell pair voltage to a plurality of resistors that are connected in series. Comparators are also provided, each of which is connected to a pole of a first battery cell of an assigned pair of battery cells and to a respective resistor on an input side and to a control electrode of a respective discharging unit on an output side.
Claims7
A device for balancing a plurality of battery cells of a battery comprising:
- an even number of n battery cells in a plurality of battery cells connected in series, wherein n is at least 4 and the n battery cells divide into n/2 pairs of adjacent battery cells;
- a plurality of charge balancing units, each charge balancing unit further comprising:
- a first battery cell in one pair of the n/2 pairs of adjacent battery cells;
- a second battery cell in the one pair of the n/2 pairs of adjacent, the second battery cell being connected in series with the first battery cell;
- a first resistor connected in series with a second resistor, the first resistor and second resistor being connected in parallel with the first battery cell and second battery cell;
- a differential amplifier having a first input connected between the first battery cell and the second battery cell, a second input connected between the first resistor and the second resistor, and an output connected between the first battery cell and the second battery cell;
- and
- a measuring device connected to the plurality of charge balancing units, the measuring device comprising:
- a first current source connected to a flow control valve to enable the measuring device to generate a current proportional to a minimum cell pair voltage of all cell pair voltages of the pairs of battery cells;
- and
- a plurality of resistors connected between the flow control valve and the first resistor in one charge balancing unit in the plurality of charge balancing units, each resistor in the plurality of resistors corresponding to one of the n/2 number of pairs of adjacent battery cells, the first current source being configured to output the current to each resistor in the plurality of resistors;
- and
- a number n/2 of first comparators, each of the first comparators including:
- a first input connected to a first pole of the first battery cell in one of the plurality of charge balancing units and a second pole of a second battery cell of another of the plurality of charge balancing units;
- a second input connected between two resistors in the plurality of resistors;
- and
- an output, each comparator being configured to compare a first voltage applied to the first input with a second voltage applied to the second input and to output a control signal dependent on a result of the comparison, wherein the output of one of the first comparators is connected to the first current source;
- and
- a plurality of discharge units, each discharge unit in the plurality of discharge units being connected in parallel to one pair of battery cells in the n/2 pairs of adjacent battery cells, each discharge unit further comprising:
- another comparator having a first input and a second input connected to the first input and the second input, respectively, of the first comparator in the plurality of first comparators corresponding to the discharge unit;
- and
- a current-limiting resistor connected in series to a switching device and the current-limiting resistor and switching device being connected in parallel to the first battery cell and the second battery cell in the one pair of battery cells, the switching device being configured to connect the current-limiting resistor to the second battery cell to complete a circuit between the first battery cell and the second battery cell in response to the control signal from the output of the comparator that is generated in response to a first voltage level present at the first input of the other comparator being greater than a second voltage level present at the second input of the other comparator, the second voltage level being a minimum voltage level for any pair of battery cells in the n/2 pairs of battery cells.
19 more elements
A battery comprising:
- a plurality of battery cells connected in series, the plurality of battery cells including an even number n of the battery cells connected in series, n is at least 4, and the n battery cells divide into n/2 pairs of adjacent battery cells;
- and
- a charge balancing device connected to the plurality of battery cells, the charge balancing device comprising:
- a plurality of charge balancing units, each charge balancing unit further comprising:
- a first battery cell in one pair of the n/2 pairs of adjacent battery cells;
- a second battery cell in the one pair of the n/2 pairs of adjacent, the second battery cell being connected in series with the first battery cell;
- a first resistor connected in series with a second resistor, the first resistor and second resistor being connected in parallel with the first battery cell and second battery cell;
- a differential amplifier having a first input connected between the first battery cell and the second battery cell, a second input connected between the first resistor and the second resistor, and an output connected between the first battery cell and the second battery cell;
- a measuring device connected to the plurality of charge balancing units, the measuring device comprising:
- a current source connected to a flow control valve to enable the measuring device to generate a current proportional to a minimum cell pair voltage of all cell pair voltages of the pairs of battery cells;
- and
- a plurality of resistors connected between the flow control valve and the first resistor in one charge balancing unit in the plurality of charge balancing units, each resistor in the plurality of resistors corresponding to one of the n/2 number of pairs of adjacent battery cells, the current source being configured to output the current to each resistor in the plurality of resistors;
- and
- a number n/2 of first comparators, each of the first comparators including:
- a first input connected to a first pole of the first battery cell in one of the plurality of charge balancing units and a second pole of a second battery cell of another of the plurality of charge balancing units;
- a second input connected between two resistors in the plurality of resistors;
- and
- an output, each comparator being configured to compare a first voltage applied to the first input with a second voltage applied to the second input and to output a control signal dependent on a result of the comparison, wherein the output of one of the first comparators is connected to the current source;
- and
- a plurality of discharge units, each discharge unit in the plurality of discharge units being connected in parallel to one pair of battery cells in the n/2 pairs of adjacent battery cells, each discharge unit further comprising:
- another comparator having a first input and a second input connected to the first input and the second input, respectively, of the first comparator in the plurality of first comparators corresponding to the discharge unit;
- and
- a current-limiting resistor connected in series to a switching device and the current-limiting resistor and switching device being connected in parallel to the first battery cell and the second battery cell in the one pair of battery cells, the switching device being configured to connect the current-limiting resistor to the second battery cell to complete a circuit between the first battery cell and the second battery cell in response to the control signal from the output of the comparator that is generated in response to a first voltage level present at the first input of the other comparator being greater than a second voltage level present at the second input of the other comparator, the second voltage level being a minimum voltage level for any pair of battery cells in the n/2 pairs of battery cells.
20 more elements
A motor vehicle comprising:
- an electric drive motor configured to drive the motor vehicle;
- and
- a battery connected to the electric drive motor, the battery including a plurality of battery cells connected in series, the plurality of battery cells including an even number n of the battery cells connected in series, n is at least 4, and the n battery cells divide into n/2 pairs of adjacent battery cells;
- and
- a charge balancing device connected to the plurality of battery cells, the charge balancing device comprising:
- a plurality of charge balancing units, each charge balancing unit further comprising:
- a first battery cell in one pair of the n/2 pairs of adjacent battery cells;
- a second battery cell in the one pair of the n/2 pairs of adjacent, the second battery cell being connected in series with the first battery cell;
- a first resistor connected in series with a second resistor, the first resistor and second resistor being connected in parallel with the first battery cell and second battery cell;
- a differential amplifier having a first input connected between the first battery cell and the second battery cell, a second input connected between the first resistor and the second resistor, and an output connected between the first battery cell and the second battery cell;
- a measuring device connected to the plurality of charge balancing units, the measuring device comprising:
- a current source connected to a flow control valve to enable the measuring device to generate a current proportional to a minimum cell pair voltage of all cell pair voltages of the pairs of battery cells;
- and
- a plurality of resistors connected between the flow control valve and the first resistor in one charge balancing unit in the plurality of charge balancing units, each resistor in the plurality of resistors corresponding to one of the n/2 number of pairs of adjacent battery cells, the current source being configured to output the current to each resistor in the plurality of resistors;
- and
- a number n/2 of first comparators, each of the first comparators including:
- a first input connected to a first pole of the first battery cell in one of the plurality of charge balancing units and a second pole of a second battery cell of another of the plurality of charge balancing units;
- a second input connected between two resistors in the plurality of resistors;
- and
- an output, each comparator being configured to compare a first voltage applied to the first input with a second voltage applied to the second input and to output a control signal dependent on a result of the comparison, wherein the output of one of the first comparators is connected to the current source;
- and
- a plurality of discharge units, each discharge unit in the plurality of discharge units being connected in parallel to one pair of battery cells in the n/2 pairs of adjacent battery cells, each discharge unit further comprising:
- another comparator having a first input and a second input connected to the first input and the second input, respectively, of the first comparator in the plurality of first comparators corresponding to the discharge unit;
- and
- a current-limiting resistor connected in series to a switching device and the current-limiting resistor and switching device being connected in parallel to the first battery cell and the second battery cell in the one pair of battery cells, the switching device being configured to connect the current-limiting resistor to the second battery cell to complete a circuit between the first battery cell and the second battery cell in response to the control signal from the output of the comparator that is generated in response to a first voltage level present at the first input of the other comparator being greater than a second voltage level present at the second input of the other comparator, the second voltage level being a minimum voltage level for any pair of battery cells in the n/2 pairs of battery cells.
22 more elements
Dependencies are inferred from the claim text.