System and method for controlling temperature of fuel cell stack

Patent metadata

Field	Value
Publication number	US-9865888-B2
Application number	US-201514639804-A
Country	US
Kind code	B2
Filing date	Mar 5, 2015
Priority date	Nov 5, 2014
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

A system and method for controlling a temperature of a fuel cell stack are provided. The method includes performing a pump OFF mode which turns off the cooling water pump or operates the cooling water pump while reducing the rotation speed of the cooling water pump to be less than the reference rotation speed, when a cooling water outlet temperature is equal to or less than a preset first temperature while a pump normal mode which adjusts a rotation speed of a cooling water pump to be equal to or greater than a preset reference rotation speed and varies rpm based on the cooling water outlet temperature is performed. In addition, the pump normal mode is performed when a cooling water outlet temperature estimation value of the fuel cell stack exceeds a preset second temperature while the pump OFF mode is performed.

First claim

What is claimed is:

1. A method for controlling a temperature of a fuel cell stack, comprising:
performing a pump OFF mode which turns off the cooling water pump or operates the cooling water pump while reducing the rotation speed of the cooling water pump to be less than the reference rotation speed, when a cooling water outlet temperature is equal to or less than a preset first temperature while a pump normal mode which adjusts a rotation speed of a cooling water pump to be equal to or greater than a preset reference rotation speed and varies revolutions per minute (rpm) based on the cooling water outlet temperature is performed;
performing the pump normal mode when a cooling water outlet temperature estimation value exceeds a preset second temperature while the pump OFF mode is performed; and
performing a low output avoidance mode which allows a power converter to reduce a voltage upper bound of a bus terminal, when a cooling water outlet temperature calculation value is equal to or less than a preset third temperature while an output normal mode in which the voltage upper bound of the bus terminal between an output terminal of the fuel cell stack and the power converter has a predetermined value is performed,
wherein the cooling water outlet temperature calculation value is a cooling water outlet temperature estimation value in the pump OFF mode and is a sensing value of the cooling water outlet temperature in the pump normal mode, and
wherein the first temperature is equal to or greater than the third temperature.

2. The method of claim 1 , wherein the pump OFF mode is performed when the cooling water outlet temperature is equal to or less than the preset first temperature and a heating value of the fuel cell stack is equal to or less than a preset first reference heating value, and the pump normal mode is performed when the cooling water outlet temperature estimation value exceeds the preset second temperature or the heating value of the fuel cell stack exceeds a preset second reference heating value.

3. The method of claim 1 , wherein the pump OFF mode is performed when the cooling water outlet temperature is equal to or less than the preset first temperature and an air outlet temperature of the fuel cell stack is less than a first air outlet temperature, and the pump normal mode is performed when the cooling water outlet temperature estimation value exceeds the preset second temperature or the air outlet temperature of the fuel cell stack exceeds a preset second air outlet temperature.

4. The method of claim 1 , wherein the pump OFF mode is performed when the cooling water outlet temperature is equal to or less than the preset first temperature and a torque value required in a motor connected to the fuel cell stack is less than a preset first required torque, and the pump normal mode is performed when the cooling water outlet temperature estimation value exceeds the preset second temperature or the torque value required in a motor connected to the fuel cell stack exceeds a preset second required torque.

5. The method of claim 1 , wherein the pump normal mode is performed when a largest value of the cooling water outlet temperature estimation value of the fuel cell stack and the cooling water outlet temperature detected by a temperature sensor exceeds the preset second temperature.

6. The method of claim 1 , wherein the preset first temperature and the preset second temperature are equal to or less than a target cooling water temperature at a cooling water inlet side.

7. The method of claim 1 , wherein the output limit value of the fuel cell stack is set using the cooling water outlet temperature estimation value.

8. The method of claim 1 , wherein the output limit value of the fuel cell stack is set based on a non-circulation of cooling water.

9. The method of claim 1 , wherein the cooling water outlet temperature estimation value of the fuel cell stack is initialized to the detected cooling water temperature just before the pump OFF mode is performed.

10. A method for controlling a temperature of a fuel cell stack, comprising:
performing a low output avoidance mode to allow a power converter to reduce a voltage upper bound of a bus terminal, when a cooling water outlet temperature is equal to or less than a preset third temperature while an output normal mode in which the voltage upper bound of the bus terminal between an output terminal of the fuel cell stack and the power converter has a predetermined value is performed; and
performing the output normal mode when the cooling water outlet temperature is equal to or greater than a preset fourth temperature while the low output avoidance mode is performed,
wherein the cooling water outlet temperature is a cooling water outlet temperature estimation value in a pump OFF mode which turns off a cooling water pump or operates the cooling water pump while reducing a rotation speed of the cooling water pump to be less than a preset reference rotation speed and is a sensing value of the cooling water outlet temperature in a pump normal mode which adjusts the rotation speed of the cooling water pump to be equal to or greater than the preset reference rotation speed and varies a revolutions per minute (rpm) based on the cooling water outlet temperature.

11. The method of claim 10 , wherein the preset third temperature and the preset fourth temperature are equal to or less than a target cooling water temperature at a cooling water inlet side.

12. The method of claim 10 , wherein in the low output avoidance mode, a charging current limit value of the power converter or a target state of charge (SOC) of the high voltage battery are increased, and in the output normal mode, the increase in the charging current limit value of the power converter or the target state of charge of the high voltage battery is released.

13. The method of claim 12 , wherein the reduction in the voltage upper bound of the bus terminal and the increase in the charging current limit value are performed within a range of an allowable charging output or an allowable state of charge of the high voltage battery.

14. The method of claim 10 , wherein the low output avoidance mode is not performed when power generation of the fuel cell stack stops.

15. The method of claim 10 , wherein the low output avoidance mode is not performed in a regenerative braking state.

16. A method for controlling a temperature of a fuel cell stack, comprising:
performing a pump OFF mode which turns off the cooling water pump or operates the cooling water pump while reducing the rotation speed of the cooling water pump to be less than the reference rotation speed, when a cooling water outlet temperature is equal to or less than a preset first temperature while a pump normal mode which adjusts a rotation speed of a cooling water pump to be equal to or greater than a preset reference rotation speed and varies revolutions per minute (rpm) based on the cooling water outlet temperature is performed; and
performing a low output avoidance mode which allows a power converter to reduce a voltage upper bound of a bus terminal, when a cooling water outlet temperature calculation value is equal to or less than a preset third temperature while an output normal mode in which the voltage upper bound of the bus terminal between an output terminal of the fuel cell stack and the power converter has a predetermined value is performed,
wherein the cooling water outlet temperature calculation value is a cooling water outlet temperature estimation value in the pump OFF mode and is a sensing value of the cooling water outlet temperature in

Assignees

• Hyundai Motor Co Ltd

Inventors

• Kwon Sang Uk

Classifications

• H01M8/04029 Primary

  Heat exchange using liquids · CPC title

• H01M8/04731

  of other components of a fuel cell or fuel cell stacks · CPC title

• H01M2250/20

  Fuel cells in motive systems, e.g. vehicle, ship, plane · CPC title

• H01M8/0435

  of cathode exhausts · CPC title

• H01M8/04358 Primary

  of the coolant · CPC title