Method of inspecting secondary battery

• US 9,091,733 B2
• Filed: 07/24/2013
• Issued: 07/28/2015
• Est. Priority Date: 07/27/2012
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Nakamura, Seigo
• Primary Examiner(s): Fantu, Yalkew
• Application Number:
  US13/949,272
• Publication Number:
  US 20140028320A1
• Time in Patent Office: 734 Days
• Field of Search: 324/426
• US Class Current: 1/1
• CPC Class Codes: G01R 31/3835 involving only voltage measurements
• CPC Class Codes: G01R 31/3865 related to manufacture, e.g. testing after manufacture
• CPC Class Codes: H01M 10/446 Initial charging measures
• CPC Class Codes: H01M 10/448 End of discharge regulating measures
• CPC Class Codes: H01M 2010/4278 Systems for data transfer from batteries, e.g. transfer of battery parameters to a controller, data transferred between battery controller and main controller
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A method of inspecting a secondary battery includes: discharging the secondary battery initially charged, at a discharge current, from an initial voltage to a discharge ending voltage; calculating an interval capacity in a voltage interval from a check starting voltage to a check ending voltage, based on the discharge current, and discharge time taken in the voltage interval; measuring a voltage change amount from a point in time when the voltage reaches a first voltage to a point in time when a length of time elapses from the above point in time, when the secondary battery is discharged from the initial voltage to the discharge ending voltage; and determining whether a total capacity satisfies a performance requirement, by comparing the calculated interval capacity with a first threshold value, and determining whether an output satisfies a performance requirement, by comparing the measured voltage change amount with a second threshold value.

Claims

1. A method of inspecting a secondary battery, comprising:

discharging the secondary battery that has been initially charged, at a given discharge current, from a given initial voltage to a discharge ending voltage;

setting a voltage interval, the voltage interval being an interval from a given check starting voltage to a check ending voltage that is lower than the check starting voltage, as a checking interval of an interval capacity of the secondary battery within a voltage range between the initial voltage and the discharge ending voltage, and calculating the interval capacity based on the discharge current, and discharge time it takes for a voltage of the secondary battery to vary from the check starting voltage to the check ending voltage;

measuring a voltage change amount as an amount of change in the voltage of the secondary battery from a first point in time at which the voltage of the secondary battery reaches a certain first voltage within the voltage range, to a second point in time at which a given length of time elapses from the first point in time, when the secondary battery is discharged from the initial voltage to the discharge ending voltage; and

determining whether a total capacity of the secondary battery having a correlation with the interval capacity satisfies a performance requirement, by comparing the calculated interval capacity with a first threshold value, and determining whether an output of the secondary battery having a correlation with the voltage change amount satisfies a performance requirement, by comparing the measured voltage change amount with a second threshold value.

2. The method according to claim 1, wherein

the first voltage and the given length of time are set to respective values that are determined so that a coefficient of correlation between the output of a secondary battery model known as a non-defective product and the voltage change amount thereof becomes equal to or larger than 0.9.

3. The method according to claim 1, wherein

it is simultaneously determined whether the total capacity satisfies the performance requirement, and whether the output satisfies the performance requirement.

4. The method according to claim 1, wherein

the voltage change amount is calculated using a result of discharge used for calculation of the interval capacity.

5. The method according to claim 1, wherein:

it is determined that the total capacity of the secondary battery satisfies the performance requirement, when the calculated interval capacity is equal to or larger than the first threshold value; and

it is determined that the output of the secondary battery satisfies the performance requirement, when the measured voltage change amount is equal to or smaller than the second threshold value.