Stop method of vehicle electrical power system

Patent metadata

Field	Value
Publication number	US-9358900-B2
Application number	US-201314093832-A
Country	US
Kind code	B2
Filing date	Dec 2, 2013
Priority date	Nov 30, 2012
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

A fuel cell system executes charge processing to charge electric power generated by a stack to a battery, and sealed discharge processing to cause an oxygen concentration inside a cathode flow channel to decrease, after a stop operation has been made on a power switch. The stop method of a fuel cell system includes: a step of calculating a remaining charge time corresponding to a time in which charge processing can be executed, by subtracting a time required in sealed discharge processing from a predetermined stop processing permitted time, after a stop operation has been made on the power switch (Step S 52 ), a step of calculating a remaining target charge amount of the battery (Step S 54 ), a step of executing charge processing while controlling output of the stack based on the remaining charge time and remaining target charge amount (Step S 56 ), and a step of executing sealed discharge processing.

First claim

What is claimed is:

1. A stop method of a vehicle electrical power system that includes:
a fuel cell that generates electric power when fuel gas is supplied to an anode flow channel and oxidant gas is supplied to a cathode flow channel;
an electrical storage device that stores electric power generated by the fuel cell;
a stop switch that generates a signal to cause electric power generation by way of the fuel cell to stop; and
a load that is driven by way of supply of electric power from the fuel cell or the electrical storage device,
wherein, after the stop switch has been operated, the system executes charge processing to charge electric power generated by the fuel cell to the electrical storage device, and concentration adjustment processing to adjust a concentration of gas inside at least one of the anode flow channel and the cathode flow channel, the method comprising the steps of:
calculating a charge time corresponding to a time in which charge processing is executable, after the stop switch has been operated, by subtracting a time required in the concentration adjustment processing from a predetermined stop processing permitted time;
calculating a target charge amount of the electrical storage device;
executing the charging processing while controlling output of the fuel cell based on the charge time and the target charge amount; and
executing the concentration adjustment processing after the charge processing has ended.

2. The stop method of a vehicle electrical power system according to claim 1 , wherein a withdrawn extent of electric power from the electrical storage device upon a next startup of the vehicle electrical power system is estimated, and the target charge amount is set to a larger value as the withdrawn extent increases, in the step of calculating a target charge amount.

3. The stop method of a vehicle electrical power system according to claim 2 , wherein it is determined whether a season in which the stop switch was operated is winter, and in a case of being winter, the target charge amount is set to a larger value than in a case of being a season other than winter, in the step of calculating a target charge amount.

4. The stop method of a vehicle electrical power system according to claim 3 , wherein it is determined whether a current startup of the vehicle electrical power system is a low-temperature startup that is a startup under a low-temperature environment, and in a case of being a low-temperature startup, a vehicle startup time corresponding to a time period since the vehicle electrical power system was started until the stop switch was operated is acquired, and in a case of the vehicle startup time being shorter than a predetermined time, the target charge amount is set to a larger value than a case of the vehicle startup time being longer than the predetermined time, in the step of calculating a target charge amount.

5. The stop method of a vehicle electrical power system according to claim 4 ,
wherein a value obtained by dividing a value obtained by subtracting a consumed energy of the load from an output energy of the fuel cell, by an energy inputted to the fuel cell in order to generate electric power with the fuel cell, is defined as net efficiency,
wherein the load includes a compressor that supplies air as oxidant gas to the cathode flow channel, and
wherein, in the step of executing the charging processing while controlling output of the fuel cell, the output of the fuel cell is controlled so that charging of the target charge amount completes within the charge time and the net efficiency in the charge processing reaches an optimum.

6. The stop method of a vehicle electrical power system according to claim 5 ,
wherein the load includes a cooling device that cools the fuel cell, and
wherein, in the step of executing the charging processing while controlling output of the fuel cell,
a net efficiency in a case of performing charge processing by controlling the output of the fuel cell to a predetermined first output value while cooling the fuel cell by way of the cooling device is calculated as a first net efficiency,
a net efficiency in a case of performing charge processing by controlling the output of the fuel cell to a second output value that is smaller than the first output value so that cooling of the fuel cell by way of the cooling device is not necessary is calculated as a second net efficiency, and
the output of the fuel cell is controlled to the first output value in a case of the first net efficiency being larger than the second net efficiency, and the output of the fuel cell is controlled to the second output value in a case of the first net efficiency being no more than the second net efficiency.

7. The stop method of a vehicle electrical power system according to claim 6 , wherein the concentration adjustment processing includes concentration reduction processing to cause an oxygen concentration inside of the cathode flow channel to decrease.

8. The stop method of a vehicle electrical power system according to claim 1 , wherein it is determined whether a season in which the stop switch was operated is winter, and in a case of being winter, the target charge amount is set to a larger value than in a case of being a season other than winter, in the step of calculating a target charge amount.

9. The stop method of a vehicle electrical power system according to claim 1 , wherein it is determined whether a current startup of the vehicle electrical power system is a low-temperature startup that is a startup under a low-temperature environment, and in a case of being a low-temperature startup, a vehicle startup time corresponding to a time period since the vehicle electrical power system was started until the stop switch was operated is acquired, and in a case of the vehicle startup time being shorter than a predetermined time, the target charge amount is set to a larger value than a case of the vehicle startup time being longer than the predetermined time, in the step of calculating a target charge amount.

10. The stop method of a vehicle electrical power system according to claim 1 ,
wherein a value obtained by dividing a value obtained by subtracting a consumed energy of the load from an output energy of the fuel cell, by an energy inputted to the fuel cell in order to generate electric power with the fuel cell, is defined as net efficiency,
wherein the load includes a compressor that supplies air as oxidant gas to the cathode flow channel, and
wherein, in the step of executing the charging processing while controlling output of the fuel cell, the output of the fuel cell is controlled so that charging of the target charge amount completes within the charge time and the net efficiency in the charge processing reaches an optimum.

11. The stop method of a vehicle electrical power system according to claim 10 ,
wherein the load includes a cooling device that cools the fuel cell, and
wherein, in the step of executing the charging processing while controlling output of the fuel cell,
a net efficiency in a case of performing charge processing by controlling the output of the fuel cell to a predetermined first output value while cooling the fuel cell by way of the cooling device is calculated as a first net efficiency,
a net efficiency in a case of performing charge processing by controlling the output of the fuel cell to a second output value that is smaller than the first output value so that cooling of the fuel cell by way of the cooling device is not necessary is calculated as a second net efficiency, and
the output of the fuel cell is controlled to the first output value in a case of the first net efficiency being larger than the s

Assignees

• Honda Motor Co Ltd

Inventors

• Wake Chihiro
• Shirasaka Takuya
• Kikuchi Go

Classifications

• B60L11/1887

  Operations & Transport · mapped topic

• B60L2210/10

  DC to DC converters · CPC title

• B60L11/1885

  Operations & Transport · mapped topic

• Y02T10/7044

  Cross-Sectional Technologies · mapped topic

• B60L1/003

  to auxiliary motors, e.g. for pumps, compressors · CPC title