Fuel cell system and operating method therefor

Patent metadata

Field	Value
Publication number	US-10193177-B2
Application number	US-201414299428-A
Country	US
Kind code	B2
Filing date	Jun 9, 2014
Priority date	Jun 20, 2007
Publication date	Jan 29, 2019
Grant date	Jan 29, 2019

Abstract

A fuel cell system and method that enables warm-up power generation corresponding to the residual water volume in the fuel cell stack without using auxiliary devices for measuring the residual water volume in the fuel cell stack. A controller computes total generated electrical energy Q by integrating of the generated current detected by current sensor during the period from start-up to shutting down of the fuel cell system, and stores the result in total generated electrical energy storage part. Also, controller measures fuel cell temperature Ts at the last shutting down cycle with temperature sensor, and stores it in power generation shutting down temperature storage part. When the fuel cell system is started, controller estimates residual water volume WR that remains in fuel cell stack 2 on the basis of fuel cell temperature Ts when power generation is shut down, total generated electrical energy Q, and fuel cell start-up temperature Tn, and sets the generated electrical power for warm-up at start-up on the basis of said residual water volume Wr.

First claim

The invention claimed is:

1. A residual water purge control system for a fuel cell system having a fuel cell stack that generates electrical power by electrochemical reaction of fuel and oxidant, a residual water estimating apparatus, and a residual water purge control device, the residual water estimating apparatus comprising:
a total generated electrical energy storage device that stores a value representing the total generated electrical energy of the fuel cell stack in the period from start-up to shutdown of power generation; and
a controller that is programmed to estimate a residual water volume that can be absorbed by a membrane electrode assembly of the fuel cell stack from a first control map that indicates a relationship between the residual water volume and said stored value in said total generated electrical energy storage device;
wherein when the stored value in said total generated electrical energy storage device is below a first prescribed level corresponding to a maximum of the residual water volume, said controller is programmed to estimate the residual water volume to be proportional to said stored value; and, when said stored value exceeds the first prescribed level, said controller is programmed to estimate the residual water volume to be inversely proportional to an increase in said stored value with respect to the first prescribed level; and
wherein when said stored value exceeds a second prescribed level larger than the first prescribed level, said controller estimates the residual water volume to be substantially constant; and
wherein the residual water purge control device is programmed to control a purging volume of the residual water purge control system based on the estimated residual water volume after the residual water has been estimated by the controller.

2. The residual water purge control system as claimed in claim 1 , wherein the stored value is proportional to the total generated electrical energy.

3. The residual water purge control system as claimed in claim 1 , wherein the stored value is selected from one of a total generated electric charge, a total quantity of generated hydrogen, a total quantity of consumed hydrogen, and a total quantity of the generated electricity.

4. The residual water purge control system as claimed in claim 1 , wherein when the stored value in said total generated electrical energy storage device exceeds the first prescribed level but not the second prescribed level, said residual water purge control device is programmed to control a purging volume of the residual water purge control system to be decreased in accordance with an increase in the total generated electricity, and wherein when the stored value in said total generated electrical energy storage device exceeds the second prescribed level, said residual water purge control device is programmed to control the purging volume of the residual water purge control system to be constant.

Assignees

• Nissan Motor

Inventors

• Kaito Takahiro
• Ikezoe Keigo

Classifications

• H01M8/04253

  Means for solving freezing problems · CPC title

• H01M8/10 Primary

  Fuel cells with solid electrolytes · CPC title

• H01M8/0432

  Temperature; Ambient temperature · CPC title

• H01M8/04228

  during shut-down · CPC title

• H01M8/04753

  of fuel cell reactants · CPC title