Management device and power supply system
Management device manages storage modules each parallel-connected to power supply through switch. Determination unit of management device, in a state where switches connected to some of power storage modules in the power storage modules are on; and switches connected to the remaining power storage modules are off, when at least one of the off-state switches are turned on, determination unit does not permit the switch to be turned on when a maximum value of current or power allowed to charge all of the power storage modules is lower than a threshold based on the maximum before the switches are is turned on.
1 . A management device that manages a plurality of power storage modules parallel-connected to a power supply through a plurality of switches including a first switch and at least one second switch, comprising:
a processor configured to:
in a state where the first switch connected to a part of the plurality of power storage modules is in an on state and the at least one second switch connected to a remaining one or more of the plurality of power storage modules is in an off state,
acquire, before the at least one second switch is turned on, a current state of charge (SOC) of each of the power storage modules,
determine a first maximum value of current or power allowed to charge the part of the plurality of power storage modules before the at least one second switch is turned on by using the current SOC of each of the plurality of power storage modules connected through the first switch,
determine a second maximum value of current or power allowed to charge all of the power storage modules by using the current SOC of each of the plurality of power storage modules connected through the first switch, assuming that the at least one second switch is turned on, and
prevent the at least one second switch from being turned on when the second maximum value is lower than a threshold based on the first maximum value.
2 . The management device of claim 1 , wherein
the first switch is connected to a power storage module with a lowest open circuit voltage among the plurality of power storage modules and is turned on when power from the power supply starts being supplied to the plurality of power storage modules, and
the at least one second switch is connected to a power storage module with a lowest open circuit voltage among the plurality of power storage modules connected to switches in an off state.
3 . A power supply system comprising:
the management device of claim 1 ; and
the plurality of power storage modules parallel-connected to the power supply through the plurality of switches including the first switch and the at least one second switch.
4 . The power supply system of claim 3 , wherein
the power supply is a motor of a mobile object or an external charger, and
when the power supply is the motor, the processor is configured to inform a control unit inside the mobile object of the second maximum value of current or power allowed to regenerate power from the motor to all of the power storage modules.
5 . The management device of claim 1 , wherein the processor is further configured to:
determine the first maximum value and the second maximum value based on SOC-maximum charge characteristics defining a relationship between the current SOC of each of the plurality of power storage modules and a third maximum value of current or power allowed to charge each of the power storage modules,
wherein the third maximum value is lower when the current SOC of each of the plurality of power storage modules is higher in the SOC-maximum charge characteristics.
6 . The management device of claim 5 , wherein the processor is further configured to:
acquire an open circuit voltage of the remaining power storage module as a connection candidate,
derive, based on the SOC-maximum charge characteristics and the current SOC of each of the plurality of power storage modules connected to the power supply, the third maximum value of current or power allowed to charge each of the plurality of power storage modules connected to the power supply,
estimate a closed circuit voltage of each of the plurality of power storage modules connected to the power supply when each of the plurality of power storage modules connected to the power supply is charged with the third maximum value, and
prevent the at least one second switch from being turned on when the open circuit voltage of the connection candidate is higher than the closed circuit voltage.
7 . The management device of claim 5 , wherein the processor is further configured to:
determine the second maximum value by estimating the second maximum value, when an open circuit voltage of each of the power storage modules connected to the power supply corresponds with an open circuit voltage of the connection candidate, based on the SOC-maximum charge characteristics, an open circuit voltage corresponding to the open circuit voltage of each of the plurality of power storage modules connected to the power supply, and an open circuit voltage corresponding to the open circuit voltage of the connection candidate, and
prevent the at least one second switch from being turned on when the second maximum value is lower than the threshold based on the first maximum value.