Screening method, screening apparatus, and method for manufacturing secondary battery

Patent metadata

Field	Value
Publication number	US-2021286013-A1
Application number	US-201716465458-A
Country	US
Kind code	A1
Filing date	Nov 21, 2017
Priority date	Nov 30, 2016
Publication date	Sep 16, 2021
Grant date	—

Abstract

A screening method according to the present invention is a screening method for screening a sheet-type battery, including a charging/discharging waveform acquisition step of acquiring a charging/discharging waveform of the sheet-type battery by charging and discharging the sheet-type battery, a step of evaluating a variation in discharging voltage over time during discharging in the sheet-type battery based on the charging/discharging waveform, a step of evaluating a variation in charging voltage over time during charging in the sheet-type battery based on the charging/discharging waveform, a step of evaluating charging efficiency of the sheet-type battery based on the charging/discharging waveform, a step of evaluating a current value at an end of the charging the sheet-type battery based on the charging/discharging waveform, and a screening step of screening the sheet-type battery based on evaluation results of the steps.

First claim

1 . A screening method for screening a unit battery, comprising:
a charging/discharging waveform acquisition step of acquiring a charging/discharging waveform of the unit battery by charging and discharging the unit battery; a first step of evaluating a variation in discharging voltage over time during discharging in the unit battery based on the charging/discharging waveform; a second step of evaluating a variation in charging voltage over time during charging in the unit battery based on the charging/discharging waveform; a third step of evaluating charging efficiency of the unit battery based on the charging/discharging waveform; a fourth step of evaluating a current value at an end of the charging of the unit battery based on the charging/discharging waveform; and a screening step of screening the unit battery based on evaluation results of the first, second, third and fourth steps.

2 . The screening method according to claim 1 , wherein in the charging/discharging waveform acquisition step, the charging/discharging waveform is acquired by charging the unit battery for a predetermined time in a CC-CV (Constant Current-Constant Voltage) manner and then discharging the unit battery in a CC (Constant Current) manner.

3 . The screening method according to claim 1 , wherein in the first step, the variation in discharging voltage over time during the discharging is evaluated based on whether or not the variation in discharging voltage over time is equal to or higher than a predetermined discharging voltage threshold.

4 . The screening method according to claim 1 , wherein in the second step, the variation in charging voltage over time during the charging is evaluated based on whether or not the variation in charging voltage over time is equal to or higher than a predetermined charging voltage threshold.

5 . The screening method according to claim 1 , wherein in the fourth step, the current value at the end of the charging is evaluated based on whether or not the current value at the end of the charging is equal to or higher than a predetermined current threshold.

6 . The screening method according to claim 1 , wherein the charging/discharging waveform is acquired again for the unit battery for which the evaluations in the first, second, third and fourth steps are satisfactory, a variation in discharging time among a plurality of charging/discharging waveforms for the unit battery is evaluated, and the unit battery is screened based on a result of the evaluation of the variation in discharging time.

7 . A method for manufacturing a secondary battery, in which the secondary battery is manufactured by connecting a plurality of unit batteries with one another, the plurality of unit batteries being screened by a screening method according to claim 1 .

8 . A screening apparatus configured to screen a unit battery, comprising:
a charger/discharger configured to charge and discharge the unit battery; a charging/discharging waveform acquisition unit configured to acquire a charging/discharging waveform of the unit battery by charging and discharging the unit battery by the charger/discharger; a discharging voltage evaluation unit configured to evaluate a variation in discharging voltage over time during discharging in the unit battery based on the charging/discharging waveform; a charging voltage evaluation unit configured to evaluate a variation in charging voltage over time during charging in the unit battery based on the charging/discharging waveform; a charging efficiency evaluation unit configured to evaluate charging efficiency of the unit battery based on the charging/discharging waveform; and a current value evaluation unit configured to evaluate a current value at an end of the charging of the unit battery based on the charging/discharging waveform.

9 . The screening apparatus according to claim 8 , wherein the charging/discharging waveform acquisition unit acquires the charging/discharging waveform by charging, by the charger/discharger, the unit battery for a predetermined time in a CC-CV manner and then discharging the unit battery in a CC manner.

10 . The screening apparatus according to claim 8 , wherein the discharging voltage evaluation unit evaluates the variation in discharging voltage over time during the discharging based on whether or not the variation in discharging voltage over time is equal to or higher than a predetermined discharging voltage threshold.

11 . The screening apparatus according to claim 8 , wherein the charging voltage evaluation unit evaluates the variation in charging voltage during the charging over time based on whether or not the variation in charging voltage over time is equal to or higher than a predetermined charging voltage threshold.

12 . The screening apparatus according to claim 8 , wherein the current value evaluation unit evaluates the current value at the end of the charging based on whether or not the current value at the end of the charging is equal to or higher than a predetermined current threshold.

13 . The screening apparatus according to claim 8 , wherein
for the unit battery for which the evaluations in the discharging voltage evaluation unit, the charging voltage evaluation unit, the charging efficiency evaluation unit, and the current value evaluation unit are satisfactory, the charging/discharging waveform acquisition unit acquires the charging/discharging waveform again by charging and discharging, by the charger/discharger, that unit battery, a variation in discharging time among a plurality of charging/discharging waveforms for the unit battery is evaluated, and the unit battery is screened based on a result of the evaluation of the variation in discharging time.

Assignees

• Nihon Micronics Kk

Inventors

• Sano Masami
• Ueki Isao
• Igarashi Masayuki

Classifications

• H02J7/80

  including monitoring or indicating arrangements · CPC title

• H01M10/48

  Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte (constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569) · CPC title

• H01M10/4285 Primary

  Testing apparatus · CPC title

• G01R31/3865 Primary

  related to manufacture, e.g. testing after manufacture · CPC title

• H01M10/44

  Methods for charging or discharging (circuits for charging H02J7/00) · CPC title