Control device and method for charging a rechargeable battery

Patent metadata

Field	Value
Publication number	US-2019044345-A1
Application number	US-201616076565-A
Country	US
Kind code	A1
Filing date	Feb 26, 2016
Priority date	Feb 26, 2016
Publication date	Feb 7, 2019
Grant date	—

Abstract

A control device for controlling charging of a rechargeable battery. The control device is configured to: determine the state of charge and the degradation of the battery before starting charging, determine a target charging curve based on the determined state of charge and degradation of the battery, the target charging curve indicating the target capacity as a function of the target voltage of the battery during charging, charge the battery thereby monitoring the capacity and the voltage of the battery, determine the voltage deviation between the target voltage and the monitored voltage based on the target charging curve and the monitored capacity, and stop charging, when the determined voltage deviation exceeds a predetermined threshold. The invention also refers to a corresponding method of controlling charging of a rechargeable battery.

First claim

1 . A control device for controlling charging of a rechargeable battery, the control device being configured to:
determine the state of charge and the degradation of the battery before starting charging, determine a target charging curve based on the determined state of charge and degradation of the battery, the target charging curve indicating the target capacity as a function of the target voltage of the battery during charging, charge the battery thereby monitoring the capacity and the voltage of the battery, determine the voltage deviation between the target voltage and the monitored voltage based on the target charging curve and the monitored capacity, and stop charging, when the determined voltage deviation exceeds a predetermined threshold.

2 . The control device according to claim 1 , further configured to:
store a plurality of predetermined target charging curves each relating to a different state of charge starting value, at which charging is started, and/or to a different degradation of the battery, and determine a target charging curve by selecting a suitable target charging curve based on the determined state of charge and degradation of the battery.

3 . The control device according to claim 1 , comprising:
a rechargeable dummy cell, a first circuit configured to charge the battery and the dummy cell, and a second circuit configured to measure the open circuit voltage of the dummy cell, the control device being further configured to: determine the open circuit voltage of the dummy cell by using the second circuit, and determine the state of charge of the battery based on the determined open circuit voltage of the dummy cell.

4 . The control device according to claim 3 , further configured to:
determine the maximum capacity increment of the battery based on the determined state of charge of the battery.

5 . The control device according to claim 4 , further configured to:
charge the battery and the dummy cell by using the first circuit, monitor the current capacity increment of the battery which has been charged, and stop charging, when the current capacity increment of the battery exceeds the determined maximum capacity increment.

6 . The control device according to claim 5 , further configured to:
determine the current capacity increment of the battery based on the charging current and the charging time of the battery, and/or based on the open circuit voltage of the dummy cell.

7 . The control device according to claim 2 , further configured to determine the degradation of the battery based on a determined degradation of the dummy cell, wherein the degradation of the battery in particular corresponds to the determined degradation of the dummy cell.

8 . The control device according to claim 7 , further configured to determine the degradation of the dummy cell based on a temperature/frequency distribution of the dummy cell and a predetermined degradation rate of the dummy cell.

9 . The control device according to claim 7 , wherein
the determination of the degradation of the dummy cell is based on the Arrhenius equation.

10 . The control device according to claim 8 , further configured to determine the temperature/frequency distribution of the dummy cell by recording for each temperature of the dummy cell how much time the dummy cell had this temperature during its lifetime.

11 . The control device according to claim 2 , configured to control charging of a battery of a specific battery type comprising a predetermined degradation rate,
wherein the dummy cell has a degradation rate which correlates with the degradation rate of the battery, and which in particular is the same degradation rate.

12 . The control device according to claim 11 , wherein the battery of the specific battery type comprises a predetermined capacity,
wherein the dummy cell has a capacity which correlates with the capacity of the battery, and which in particular is the same capacity.

13 . The control device according to claim 2 , comprising a voltage sensor for detecting the open circuit voltage of the dummy cell.

14 . The control device according to claim 2 , comprising a temperature sensor for detecting the temperature of the dummy cell and/or the battery.

15 . A battery pack comprising:
at least one battery, in particular a solid state bipolar battery, and
a control device according to claim 1 .

16 . A battery charging system comprising:
at least one battery, in particular a solid state bipolar battery, a charging device for the battery, and a control device according to claim 1 .

17 . A vehicle comprising:
an electric motor, and a battery pack according to claim 15 .

18 . A vehicle comprising:
an electric motor, at least one battery, in particular a solid state bipolar battery, and a control device according to claim 1 .

19 . A method of controlling charging of a rechargeable battery, the method comprising the steps of:
determining the state of charge and the degradation of the battery before starting charging, determining a target charging curve based on the determined state of charge and degradation of the battery, the target charging curve indicating the target capacity as a function of the target voltage of the battery during charging, charging the battery thereby monitoring the capacity and the voltage of the battery, determining the voltage deviation between the target voltage and the monitored voltage based on the target charging curve and the monitored capacity, and stopping charging, when the determined voltage deviation exceeds a predetermined threshold.

20 . The method according to claim 19 , further comprising the steps of:
storing a plurality of predetermined target charging curves each relating to a different state of charge starting value, at which charging is started, and/or to a different degradation of the battery, and determining a target charging curve by selecting a suitable target charging curve based on the determined state of charge and degradation of the battery.

21 . The method according to claim 20 , wherein a first circuit is used to charge the battery and a rechargeable dummy cell, and a second circuit is used to measure the open circuit voltage of the dummy cell, the method comprising the steps of:
determining the open circuit voltage of the dummy cell by using the second circuit, and determining the state of charge of the battery based on the determined open circuit voltage of the dummy cell.

22 . The method according to claim 21 , further comprising:
determining the maximum capacity increment of the battery based on the determined state of charge of the battery.

23 . The method according to claim 22 , further comprising the steps of:
charging the battery and the dummy cell by using the first circuit, monitoring the current capacity increment of the battery which has been charged, and stopping charging, when the current capacity increment of the battery exceeds the determined maximum capacity increment.

24 . The method according to claim 23 , wherein the current capacity increment of the battery is determined based on the charging current and the charging time of the battery, and/or based on the open circuit voltage of the dummy cell.

25 . The method according to claim 20 , wherein the degradation of the battery is determined based on a determined degradation of the dummy cell, wherein the d

Assignees

• Toyota Motor Europe

Inventors

• Komiyama Keita
• Katoh Yuki

Classifications

• H02J7/875

  Charging or discharging for charge maintenance, battery initiation or rejuvenation · CPC title

• H02J7/61

  against overcharge · CPC title

• H02J7/947

  in response to integrated charge or discharge current · CPC title

• H02J7/825

  Detection of fully charged condition · CPC title

• H02J7/96

  in response to battery voltage · CPC title