Capacity estimation method and capacity estimation system for power storage device

Patent metadata

Field	Value
Publication number	US-2020292624-A1
Application number	US-201816753839-A
Country	US
Kind code	A1
Filing date	Oct 25, 2018
Priority date	Nov 2, 2017
Publication date	Sep 17, 2020
Grant date	—

Abstract

It is difficult to know the remaining amount and the degradation state of a power storage device, and it is also difficult to estimate how long the power storage device can be used. Data obtained through midway discharge and mid-to-full charge is used as the learning data to calculate the degradation state and the capacity. In other words, the learning data includes both a discharge curve of midway discharge and a charge curve of mid-to-full charge, and neural network processing is performed with the use of the learned data.

First claim

1 . A capacity estimation method for a power storage device comprising a plurality of lithium-ion secondary batteries, comprising:
performing self-discharging of a secondary battery with an SOC of 100% over time during a first period; charging the secondary battery from an SOC of a self-discharged state to a fully charged state during a second period; discharging the secondary battery to SOC 80% using a discharging circuit during a third period; charging the secondary battery to a fully charged state using a charging circuit; and calculating the remaining capacity at the fully charged state from the discharge data of the discharging to SOC 80% and the charge data from SOC 80% to SOC 100% by neural network processing.

2 . The capacity estimation method according to claim 1 ,
wherein the power storage device installed in an uninterruptible power supply system, and wherein the charge from SOC 80% to SOC 100% is performed by constant voltage charging.

3 . A capacity estimation system for a power storage device comprising a plurality of lithium-ion secondary batteries connected in series, comprising:
performing self-discharging of a secondary battery with an SOC of 100% with a constant load during a first period; charging the secondary battery from an SOC of a self-discharged state to a fully charged state during a second period; discharging the secondary battery to SOC 80% using a discharging circuit during a third period; charging the secondary battery to a fully charged state using a charging circuit; and calculating the remaining capacity at the fully charged state from the charge data from SOC 80% to SOC 100% by neural network processing.

4 . The capacity estimation method according to claim 1 , wherein the power storage device is a lithium-ion secondary battery installed inside an uninterruptible power supply.

5 . The capacity estimation method according to claim 1 , wherein the power storage device is a lithium-ion secondary battery installed inside a vehicle.

6 . The capacity estimation system according to claim 3 , wherein the power storage device is a lithium-ion secondary battery installed inside an uninterruptible power supply.

7 . The capacity estimation system according to claim 3 , wherein the power storage device is a lithium-ion secondary battery installed inside a vehicle.

Assignees

• Semiconductor Energy Lab

Inventors

• Tajima Ryota
• Isa Toshiyuki
• Chida Akihiro

Classifications

• H02J2105/37

  exchanging power with electric vehicles [EV] or with hybrid electric vehicles [HEV] · CPC title

• H02J7/84

  Control of state of health [SOH] · CPC title

• H02J7/82 Primary

  Control of state of charge [SOC] · CPC title

• Y02E60/10

  Energy storage using batteries · CPC title

• G01R31/392

  Determining battery ageing or deterioration, e.g. state of health · CPC title