Method for evaluating a power storage device and method for producing the power storage device
A method for evaluating a connection resistance between a positive current collecting part of an electrode body of a battery and a positive inner terminal member connected thereto includes: changing a power storage device with a first battery voltage by CCCV charging or CCCV discharging into a second battery voltage; obtaining an evaluation value for evaluating the connection resistance by use of at least two values of the following values: CC electric quantity, CV electric quantity, CCCV electric quantity, CC time, CV time, CCCV time, and CV termination current value of the power storage device; and evaluating a connection resistance of the power storage device based on the evaluation value.
1 . A method for evaluating a power storage device by evaluating connection resistance between a current collecting part of an electrode body and a terminal member connected to the current collecting part in the power storage device,
wherein the method comprises:
changing a device voltage of the power storage device from a first device voltage to a second device voltage by constant-current constant-voltage (CCCV) charging or CCCV discharging;
obtaining any one of a quantity ratio of constant voltage (CV) electric quantity/constant current (CC) electric quantity, a time ratio of CV time/CC time, a quantity ratio of CV electric quantity/CCCV electric quantity, a time ratio of CV time/CCCV time, a ratio of the CV termination current value/CC electric quantity, a time ratio of the CV termination current value/CC time, a quantity ratio of CC electric quantity/CV electric quantity, a quantity ratio of CCCV electric quantity/CV electric quantity, a time ratio of CCCV time/CV time, CC electric quantity/CV termination current value, CC time/CV termination current value, a quantity ratio of CC electric quantity/CV electric quantity, (CC electric quantity-CV electric quantity)×(CC time-CV time), as an evaluation value for evaluating the connection resistance by use of at least two values from among CC electric quantity, CV electric quantity, CCCV electric quantity, CC time, CV time, CCCV time, and CV termination current value of the power storage device, which are obtained in the changing of the device voltage;
evaluating the connection resistance of the power storage device based on the evaluation value; and
eliminating the power storage device as defective in response to the evaluated connection resistance exceeding a threshold value.
2 . The method for evaluating a power storage device according to claim 1 , wherein
in the obtaining of the evaluation value,
a quantity ratio of CV electric quantity/CC electric quantity is obtained as the evaluation value.
3 . The method for evaluating a power storage device according to claim 1 , wherein
in the obtaining of the evaluation value,
a time ratio of CV time/CC time is obtained as the evaluation value.
4 . A method for producing a power storage device, the method comprising sorting the connection resistance of the power storage device by the method for evaluating the power storage device set forth in claim 1 .
5 . A method for producing a power storage device, the method comprising sorting the connection resistance of the power storage device by the method for evaluating the power storage device set forth in claim 2 .
6 . A method for producing a power storage device, the method comprising sorting the connection resistance of the power storage device by the method for evaluating the power storage device set forth in claim 3 .