Battery pack and electric power consuming apparatus
View Patent ↗A battery pack that has a configuration in which a plurality of secondary battery cells are connected in series at time of discharge and are connected in parallel at time of charge, and that has a configuration and a structure with which the charge and the discharge are allowed to be performed without any trouble even if an abnormal-state secondary battery cell exists is provided. A battery pack 10 includes a plurality of secondary battery cells 21 and a control circuit 11 . Under control of the control circuit 11 , the plurality of secondary battery cells 21 are connected in series at time of discharge, and are connected in parallel at time of charge. The control circuit 11 measures voltages of the respective secondary battery cells 21 before the charge, and in a state that a secondary battery cell 21 having a value of measured voltage equal to or less than a predetermined value as an abnormal-state secondary battery cell is electrically disconnected from other secondary battery cells 21 in the plurality of secondary battery cells 21 , the control circuit 11 connects the other secondary battery cells 21 in parallel and charges the other secondary battery cells 21.
1. A battery pack comprising:
a plurality of secondary battery cells; and
a control circuit, wherein
under control of the control circuit, the plurality of secondary battery cells are connected in series at time of discharge,
the control circuit connects the secondary battery cells in series and charges the secondary battery cells until each electric power amount thereof reaches a predetermined electric power amount, and subsequently measures a voltage of the secondary battery cells connected in series,
when a value of the measured voltage of the secondary battery cells connected in series exceeds a first predetermined value, the control circuit switches connection of the secondary battery cells to parallel connection, charges the secondary battery cells, and completes the charge, and
when the value of the measured voltage of the secondary battery cells connected in series is equal to or less than the first predetermined value, the control circuit measures voltages of the respective secondary battery cells, and in a state that a secondary battery cell having the value of the measured voltage equal to or less than a second predetermined value as an abnormal-state secondary battery cell is electrically disconnected from other secondary battery cells in the plurality of secondary battery cells, the control circuit connects the other secondary battery cells in parallel, charges the other secondary battery cells, and completes the charge.
2. The battery pack according to claim 1 , wherein the control circuit discharges the secondary battery cells in a state that the abnormal-state secondary battery cell is connected in series with the other secondary battery cells.
3. An electric power consuming apparatus comprising the battery pack according to claim 1 .
4. An electric power consuming apparatus comprising the battery pack according to claim 2 .
5. The battery pack according to claim 1 , wherein the control circuit includes a voltage measurement device.
6. The battery pack according to claim 1 , wherein the control circuit includes a charge and discharge control circuit.
7. The battery pack according to claim 6 , wherein the charge and discharge control circuit includes a battery protection circuit.
8. The battery pack according to claim 1 , wherein a switching device is arranged between the control circuit and each of the secondary battery cells.
9. The battery pack according to claim 1 , wherein the predetermined electric power amount is 80% or less than a capacity of each of the secondary battery cells.
10. The battery pack according to claim 1 , wherein the first predetermined value is obtained by subtracting a value from 0.05 volts to 0.2 volts both inclusive from a product of a value obtained by adding a voltage measurement error to a nominal voltage and the number of the secondary battery cells in series.
11. The battery pack according to claim 1 , wherein the second predetermined value is obtained by subtracting a value from 0.05 volts to 0.5 volts both inclusive from a nominal voltage.