Control system, control method, and storage medium

1. A control system that controls transfer of electric power between a power grid and a secondary battery that is mounted in a vehicle and stores electric power for travel, comprising:

a determiner configured to determine whether a state in which first electric power or second electric power is equal to or less than a threshold continues for a predetermined time on the basis of a detection result of the first electric power or the second electric power, wherein the first electric power is a first amount of electric power that is transferred from the power grid to the secondary battery per unit of time when the power grid provides the secondary battery with the electric power, and wherein the second electric power is a second amount of electric power that is transferred from the secondary battery to the power grid per unit of time when the secondary battery provides the power grid with the electric power; and

a controller configured to cause the transfer of electric power between the power grid and the secondary battery to stop when the determiner determines that the state in which the first electric power or the second electric power is equal to or less than the threshold continues for the predetermined time.

2. The control system according to claim 1 ,

wherein the determiner and the controller are connected to the vehicle by a cable and are embedded in a charging device that mediates the transfer of electric power between the power grid and the secondary battery.

3. The control system according to claim 1 ,

wherein the determiner and the controller are mounted in the vehicle and are embedded in a control device that controls charging and discharging of electric power of the secondary battery.

4. The control system according to claim 1 ,

wherein the determiner determines whether a detection result of a charging state of the secondary battery at a timing at which the transfer of electric power is stopped has reached an upper limit value of the charging state or a lower limit value of the charging state, and

the controller stops the transfer of electric power between the power grid and the secondary battery when the determiner determines that the detection result has reached the upper limit value of the charging state or the lower limit value of the charging state and even when a request for charging and discharging of the secondary battery is received from an external device.

5. The control system according to claim 1 ,

wherein, when a detection result of the charging state of the secondary battery at the timing at which the transfer of electric power is stopped has reached an upper limit value of the charging state, the controller stops the transfer of electric power between the power grid and the secondary battery for a predetermined time or until the detection result falls below a lower limit value of the charging state.

6. A control method comprising:

by a computer that controls transfer of electric power between a power grid and a secondary battery that is mounted in a vehicle and stores electric power for travel,

determining whether a state in which first electric power or second electric power is equal to or less than a threshold continues for a predetermined time on the basis of a detection result of the first electric power or the second electric power, wherein the first electric power is a first amount of electric power that is transferred from the power grid to the secondary battery per unit of time when the power grid provides the secondary battery with the electric power, and wherein the second electric power is a second amount of electric power that is transferred from the secondary battery to the power grid per unit of time when the secondary battery provides the power grid with the electric power; and

causing the transfer of electric power between the power grid and the secondary battery to stop when the state in which the first electric power or the second electric power is equal to or less than the threshold continues for the predetermined time.

7. A non-transitory computer-readable storage medium that stores a computer program to be executed by a computer that controls transfer of electric power between a power grid and a secondary battery that is mounted in a vehicle and stores electric power for travel, to perform at least:

determining whether a state in which first electric power or second electric power is equal to or less than a threshold continues for a predetermined time on the basis of a detection result of the first electric power or the second electric power, wherein the first electric power is a first amount of electric power that is transferred from the power grid to the secondary battery per unit of time when the power grid provides the secondary battery with the electric power and wherein the second electric power is a second amount of electric power that is transferred from the secondary battery to the power grid per unit of time when the secondary battery provides the power grid with the electric power; and

causing the transfer of electric power between the power grid and the secondary battery to stop when the state in which the first electric power or the second electric power is equal to or less than the threshold continues for the predetermined time.

8. The control system according to claim 1 ,

wherein the first electric power is a first instantaneous value of electric power with which the power grid provides the secondary battery, and

the second electric power is a second instantaneous value of electric power with which the secondary battery provides the power grid.

9. The control system according to claim 1 ,

wherein the determiner is configured to determine whether an SOC (State of Charge) of the secondary battery reaches an upper limit threshold,

the controller is configured to cause the charging of the secondary battery to stop when the charging of the secondary battery is executing and the SOC of the secondary battery reaches the upper limit threshold, and

the controller is configured to cause the transfer of electric power between the power grid and the secondary battery to stop when the determiner determines that the state in which the first electric power or the second electric power is equal to or less than the threshold continues for the predetermined time in a case in which the transfer of electric power between the power grid and the secondary battery continues.

10. The control system according to claim 9 ,

wherein the first electric power is a first instantaneous value of electric power with which the power grid provides the secondary battery,

the second electric power is a second instantaneous value of electric power with which the secondary battery provides the power grid.

11. The control system according to claim 1 ,

wherein the determiner is configured to determine whether an SOC (State of Charge) of the secondary battery reaches an upper limit threshold and to determine whether the SOC of the secondary battery reaches a lower limit threshold,

the controller is configured to cause the charging of the secondary battery to stop when the charging of the secondary battery is executing and the SOC of the secondary battery reaches the upper limit threshold,

the controller is configured to cause the discharging of the secondary battery to stop when the discharging of the secondary battery is executing and the SOC of the secondary battery reaches the lower limit threshold, and

the controller is configured to cause the transfer of electric power between the power grid and the secondary battery to stop when the determiner determines that the state in which the first electric power or the second electric power is equal to or less than the threshold continues for the predetermined time in a case in which the transfer of electric power between the power grid and the secondary battery continues.

12. The control system according to claim 11 ,

wherein the first electric power is a first instantaneous value of electric power with which the power grid provides the secondary battery,

the second electric power is a second instantaneous value of electric power with which the secondary battery provides the power grid.