Systems and methods for battery discharge control

Patent metadata

Field	Value
Publication number	US-10601083-B2
Application number	US-201616076091-A
Country	US
Kind code	B2
Filing date	Feb 17, 2016
Priority date	Feb 17, 2016
Publication date	Mar 24, 2020
Grant date	Mar 24, 2020

Abstract

A discharging control system for a battery includes temperature sensing means configured to provide a temperature value associated with the battery, voltage sensing means configured to provide a voltage value associated with the battery, pressure sensing means configured to provide a pressure value associated with an internal portion of the battery, and a controller. The controller is configured to determine, before a discharging process is started, a threshold pressure change associated with a discharge of the battery based on map data selected from a predetermined data map associated with the battery, monitor, during the discharging process, a present voltage value obtained by the voltage sensing means, a current pressure value, and a total pressure change based on the current pressure value obtained by the pressure sensing means, permit continuation of the discharging process when the present voltage value falls below a first lower limit voltage value if the total pressure change is less than the threshold pressure change and the current pressure value is greater than a predetermined minimum threshold pressure, and prohibit continuation of the discharging process when any one of the following conditions is true: (i) the present voltage value falls below a second lower limit voltage value that is lower than the first lower limit voltage value; (ii) the total pressure change is greater than or equal to the threshold pressure change; or (iii) the current pressure value is lower than the predetermined minimum threshold pressure.

First claim

The invention claimed is:

1. A discharging control system for a battery, comprising:
a temperature sensor configured to provide a temperature value associated with the battery;
a voltage sensor configured to provide a voltage value associated with the battery;
a pressure sensor configured to provide a pressure value associated with an internal portion of the battery; and
a controller configured to:
determine, before a discharging process is started, a threshold pressure change associated with a discharge of the battery based on map data selected from a predetermined data map associated with the battery;
monitor, during the discharging process, a present voltage value obtained by the voltage sensor, a current pressure value, and a total pressure change based on the current pressure value obtained by the pressure sensor;
permit continuation of the discharging process when the present voltage value falls below a first lower limit voltage value if the total pressure change is less than the threshold pressure change and the current pressure value is greater than a predetermined minimum threshold pressure; and
prohibit continuation of the discharging process when any one of the following conditions is true:

(i) the present voltage value falls below a second lower limit voltage value that is lower than the first lower limit voltage value;
(ii) the total pressure change is greater than or equal to the threshold pressure change; or
(iii) the current pressure value is lower than the predetermined minimum threshold pressure.

2. The discharging control system according to claim 1 , wherein the selection of the map data is based on a pre-discharging temperature value obtained from the temperature sensor, a pre-discharging voltage value obtained from the voltage sensor, and a pre-discharging pressure value obtained from the pressure sensor.

3. The discharging control system according to claim 1 , wherein the controller is configured to decrease the first lower limit voltage value when the present voltage value falls below the first lower limit voltage value, if the total pressure change is less than the threshold pressure change and the current pressure value is higher than the minimum predetermined pressure.

4. The discharging control system according to claim 1 , wherein the controller is further configured to compensate for creep in one or more portions of the battery by modifying at least one of the pressure information based on an initial internal pressure measurement, the pre-discharging process pressure value, and the pre-discharging temperature value.

5. The discharging control system according to claim 4 , wherein the controller is configured to compare the initial internal pressure measurement and the pre-discharging pressure value, and when the initial internal pressure measurement is greater than the pre-discharging process pressure value, select new map data associated with the pre-charging pressure value.

6. The discharging control system according to claim 5 , wherein the predetermined map comprises a collection of experimentally measured internal pressures, open circuit voltages, and temperatures of a representative battery under representative conditions of use of the battery.

7. The discharging control system according to claim 1 , wherein the pressure sensor comprises at least one tactile sensor embedded in the battery.

8. The discharging control system according to claim 7 , wherein the at least one tactile sensor is positioned parallel to a laminated direction of a battery cell of the battery.

9. The discharging control system according to claim 1 , further comprising a state of charge sensor configured to determine a state of charge of the battery.

10. The discharging control system according to claim 1 , wherein the voltage sensor comprises a dummy cell connected to one or more battery packs associated with the battery.

11. The discharging control system according to claim 1 , wherein the voltage value is an open circuit voltage of the battery.

12. The charging control system according to claim 1 , wherein the battery comprises at least one of a lithium-ion solid-state battery and a lithium-ion liquid electrolyte battery.

13. A vehicle comprising the discharging control system according to claim 1 .

14. A method for discharging a battery, comprising:
determining a temperature value associated with the battery;
determining a voltage value associated with the battery;
determining a pressure value associated with an internal portion of the battery;
determining, before a discharging of the battery is started, a threshold pressure change associated with a full discharge of the battery based on map data selected from a predetermined data map associated with the battery;
discharging the battery;
monitoring, during the discharging, a present voltage value obtained by the voltage sensor and a total pressure change based on a present pressure value obtained by the pressure sensor;
permitting continuation of the discharging process when the present voltage value falls below a first lower limit voltage value if the total pressure change is less than the threshold pressure change and the current pressure value is greater than a predetermined minimum threshold pressure; and
prohibiting continuation of the discharging process when any one of the following conditions is true:
(i) the present voltage value falls below a second lower limit voltage value that is lower than the first lower limit voltage value;
(ii) the total pressure change is greater than or equal to the threshold pressure change; or
(iii) the current pressure value is lower than the predetermined minimum threshold pressure.

15. The method according to claim 14 , wherein the selection of the map data is based on a pre-charging temperature value obtained from the temperature sensor, a pre-charging voltage value obtained from the voltage sensor, and a pre-charging pressure value obtained from the pressure sensor.

16. The method according to claim 14 comprising decreasing the upper limit voltage value when the present voltage value falls below the lower limit voltage value, and the total pressure change is less than the threshold pressure change.

17. The method according to claim 14 , comprising compensating for creep in one or more portions of the battery by modifying the selected map data based on an initial internal pressure measurement, the pre-charging process pressure value, and the pre-charging temperature value.

18. The method according to claim 17 , comprising comparing the initial internal pressure measurement and the pre-discharging pressure value; and
when the initial internal pressure measurement is greater than the pre-discharging process pressure value, selecting new map data associated the pre-discharging pressure value.

19. The method according to claim 18 , wherein the new threshold pressure change is set based on a predetermined map created as a function of experimentally measured internal pressures, open circuit voltages, and temperatures of a representative battery under representative conditions.

20. The method according to claim 14 , comprising determining a state of charge of the battery and modifying the threshold pressure change based on the state of charge of the battery before the discharging is started.

21. The method according claim 14 , wherein the battery comprises at least one of a lithium-ion solid-state battery and a lithium-ion liquid electrolyte battery.

Assignees

• Toyota Motor Europe

Inventors

• Komiyama Keita
• Katoh Yuki

Classifications

• H01M10/443

  in response to temperature · CPC title

• H02J2007/004

  Electricity · mapped topic

• H02J2007/0067

  Electricity · mapped topic

• H01M10/448 Primary

  End of discharge regulating measures · CPC title

• H02J7/0063

  Electricity · mapped topic