Power supply device having a control device that calculates a first index indicating an amount of decrease in an electrolyte solution
A power supply device includes a secondary cell, a detection device, a storage device, and a control device. The secondary cell includes an electrolyte solution. The detection device detects the voltage and temperature of the secondary cell. The storage device stores first information and second information. The first information indicates the relationship among the voltage, the temperature, and the amount of decrease in the electrolyte solution during energization of the secondary cell. The second information indicates the relationship among the voltage, the temperature, and the amount of decrease in the electrolyte solution during storage of the secondary cell. The control device calculates a first index indicating the amount of decrease in the electrolyte solution.
1 . A power supply device comprising:
a secondary cell including an electrolyte solution;
a detection device configured to detect a voltage of the secondary cell and a temperature of the secondary cell;
a storage device configured to store
first information indicating a relationship among the voltage of the secondary cell, the temperature of the secondary cell, and an amount of decrease in the electrolyte solution during energization of the secondary cell, and
second information indicating a relationship among the voltage of the secondary cell, the temperature of the secondary cell, and the amount of decrease in the electrolyte solution during storage of the secondary cell; and
a control device configured to calculate a first index indicating the amount of decrease in the electrolyte solution, wherein
the first index includes
a second index indicating the amount of decrease in the electrolyte solution due to energization of the secondary cell, and
a third index indicating the amount of decrease in the electrolyte solution due to storage of the secondary cell,
the control device is configured to:
calculate the second index based on the voltage and the temperature detected by the detection device and the first information, when the secondary cell is energized, and
calculate the third index based on the voltage and the temperature detected by the detection device and the second information, when the secondary cell is stored, and
determines whether the secondary cell is energized or stored based on whether a current of the secondary cell is zero.
2 . The power supply device according to claim 1 , wherein:
the first information is created based on results of a cycle test of the secondary cell performed for each temperature; and
the second information is created based on results of a storage test of the secondary cell performed for each temperature and each voltage.
3 . The power supply device according to claim 2 , wherein the control device is configured to output a command to notify an alert when the first index is greater than a first threshold.
4 . The power supply device according to claim 3 , wherein the control device is configured to output a command to limit input and output power of the secondary cell when the first index is equal to or less than the first threshold and greater than a second threshold that is smaller than the first threshold.
5 . The power supply device according to claim 4 , wherein the control device is configured to output a command to limit an upper limit voltage value of the secondary cell when the first index is equal to or less than the second threshold and greater than a third threshold that is smaller than the second threshold.
6 . The power supply device according to claim 1 , wherein:
the secondary cell includes an electrode assembly having an aspect ratio of 1.5 or more;
the electrode assembly is composed of a stack of a positive electrode, a negative electrode, and a separator located between the positive electrode and the negative electrode; and
the separator includes a functional layer having a function to bond the positive electrode and the negative electrode to the separator.
7 . The power supply device of claim 1 , wherein the control device calculates and updates the first index for each cell included in the battery.
8 . The power supply device of claim 1 , wherein the control device separately calculates the amount of decrease in the electrolyte solution due to energization and due to storage by selectively using the first information and the second information, and updates the first index as a cumulative sum of the calculated decreases.