Recovery control method for secondary battery, recovery control system for secondary battery, and vehicle control system

1. A recovery control method for a secondary battery, the secondary battery including a positive electrode containing a positive electrode active material, a solid electrolyte, and a negative electrode containing a negative electrode active material containing at least a lithium metal or a lithium alloy, the secondary battery being fastened from an outside, the recovery control method comprising:

measuring cell resistance of the secondary battery;

calculating a recovery limit resistance value indicating an upper limit value of resistance that ensures recovering the secondary battery from a depth of charge/discharge of the secondary battery, a cell temperature of the secondary battery, and a pressure applied to the secondary battery; and

inhibiting charging/discharging the secondary battery and executing recovery control that recovers the secondary battery when a resistance value of the cell resistance is equal to or less than the recovery limit resistance value.

2. The recovery control method according to claim 1 , comprising:

calculating a necessary recovery period necessary for recovering the secondary battery from at least one parameter of the depth of charge/discharge, the cell temperature, and the pressure applied to the secondary battery; and

setting a charge parameter for charging the secondary battery and/or an execution parameter for executing the recovery control so as to shorten the necessary recovery period when the necessary recovery period is longer than a predetermined period.

3. The recovery control method according to claim 1 , wherein

the recovery control includes pressurizing control that applies a pressure equal to or more than a pressure that causes a creep deformation of the negative electrode to the secondary battery.

4. The recovery control method according to claim 1 , wherein the recovery control includes temperature control that increases the cell temperature to higher than a current temperature of the secondary battery.

5. The recovery control method according to claim 1 , wherein a depth of charge of the secondary battery when the recovery control is started is set to equal to or more than a predetermined depth of charge.

6. The recovery control method according to claim 1 , comprising:

calculating a necessary recovery period necessary for recovering the secondary battery from at least one parameter of the depth of charge/discharge, the cell temperature, and the pressure applied to the secondary battery;

calculating a charging period of the secondary battery corresponding to a length of the calculated necessary recovery period; and

charging the secondary battery for the charging period before the recovery control.

7. The recovery control method according to claim 1 , wherein the secondary battery is charged and discharged after the recovery control recovers the secondary battery.

8. The recovery control method according to claim 1 , wherein

when the resistance value of the cell resistance is higher than the recovery limit resistance value, a plurality of parameters of the depth of charge of the secondary battery, the cell temperature, and the pressure applied to the secondary battery are increased so as to increase the recovery limit resistance value.

9. A recovery control system comprising:

a secondary battery including a positive electrode containing a positive electrode active material, a solid electrolyte, and a negative electrode containing a negative electrode active material containing a lithium metal or a lithium alloy, the secondary battery being fastened from an outside;

a measuring device that measures cell resistance of the secondary battery; and

a controller that executes recovery control that recovers the secondary battery, wherein the controller:

calculates a recovery limit resistance value indicating an upper limit value of resistance that ensures recovering the secondary battery from a depth of charge/discharge of the secondary battery, a cell temperature of the secondary battery, and a pressure applied to the secondary battery; and

inhibits charging/discharging the secondary battery and executes the recovery control when a resistance value of the cell resistance is equal to or less than the recovery limit resistance value.

10. A vehicle control system comprising

the recovery control system according to claim 9 , wherein

the vehicle control system controls a vehicle using the secondary battery as a power source, and

the controller executes the recovery control while the vehicle stops.

11. The vehicle control system according to claim 10 , wherein the controller:

compares the resistance value of the cell resistance with a resistance threshold value set corresponding to the recovery limit resistance value; and

gives a driver of the vehicle a notification for recommending stopping the vehicle when the resistance value of the cell resistance is higher than the resistance threshold value.

12. A vehicle control system comprising

the recovery control system according to claim 9 , wherein

the vehicle control system controls a hybrid vehicle with an engine and a motor coupled to the secondary battery, and

the controller inhibits charging/discharging the secondary battery and executes the recovery control during a travel mode for travelling only with the engine.