Fuel cell system and dryness degree acquisition method

Patent metadata

Field	Value
Publication number	US-10276883-B2
Application number	US-201514920064-A
Country	US
Kind code	B2
Filing date	Oct 22, 2015
Priority date	Nov 15, 2014
Publication date	Apr 30, 2019
Grant date	Apr 30, 2019

Abstract

A fuel cell system, comprising: a measurer that measures an impedance of the fuel cell; a controller that controls an operation state of the fuel cell; and an acquirer that acquires a dryness degree of the fuel cell from the measured impedance when the operation state is a first operation state, and acquires the dryness degree of the fuel cell as a wet state when the operation state is a second operation state in which a water balance is more than the first operation state.

First claim

What is claimed is:

1. A fuel cell system, comprising: a measurer configured to measure an impedance of the fuel cell using a single frequency; a controller programmed to control an operation state of the fuel cell; and an acquirer programmed to acquire a temperature of the fuel cell, wherein when the temperature of the fuel cell is equal to or above a predetermined value, the operation state is determined as a first operation state, and when the temperature is less than the predetermined value, the operation state is determined as a second operation state having a water balance higher than that of the first operation state, wherein the water balance indicates a water content in the fuel cell, acquire a dryness degree of the fuel cell from a real part of the measured impedance, when the real part of the measured impedance is smaller than a reference value, determine the dryness degree as a wet state, when the operation state is the first operation state, determine the dryness degree based on the real part of the measured impedance, and when the operation state is the second operation state, acquire the dryness degree of the fuel cell as a wet state, wherein when it is acquired, by the acquirer, that the dryness degree is a dry state, the controller controls humidification of the fuel cell such that the water balance is more than that of the first operation state.

2. The fuel cell system according to claim 1 , wherein the acquirer is programmed to acquire the real part on the basis of measurement by the measurer when the operation state is the first operation state, and the real part is considered to be a value that is smaller than the reference value when the operation state is the second operation state.

3. A fuel cell system, comprising: a measurer configured to measure an impedance of the fuel cell using a single frequency; a controller programmed to control an operation state of the fuel cell; an acquirer programmed to acquire a temperature of the fuel cell, wherein when the temperature of the fuel cell is equal to or above a predetermined value, the operation state is determined as a first operation state, and when the temperature is less than the predetermined value, the operation state is determined as a second operation state having a water balance higher than that of the first operation state, wherein the water balance indicates a water content in the fuel cell, acquire a dryness degree of the fuel cell from a real part of the measured impedance, when the real part of the measured impedance is smaller than a reference value, determine the dryness degree as a wet state, when the operation state is the first operation state, determine the dryness degree based on the real part of the measured impedance, and when the operation state is the second operation state, acquire the dryness degree of the fuel cell from the real part of the measured impedance measured by the measurer during the first operation state, wherein when it is acquired, by the acquirer, that the dryness degree is a dry state, the controller controls humidification of the fuel cell such that the water balance is more than that of the first operation state.

4. A method of acquiring a dryness degree of a fuel cell, the method comprising:
acquiring a temperature of the fuel cell,
determining, when the temperature of the fuel cell is equal to or above a predetermined value, an operation state of the fuel cell is a first operation state, and when the temperature is less than the predetermined value, the operation state is a second operation state having a water balance higher than that of the first operation state, wherein the water balance indicates a water content in the fuel cell;
acquiring the dryness degree of the fuel cell from a real part of a measured value of an impedance of the fuel cell when the operation state of the fuel cell is the first operation state, wherein when the real part of the measured value of the impedance is smaller than a reference value, the dryness degree is determined as a wet state; and
determining the dryness degree as a wet state when the operation state is the second operation state, wherein
the impedance is measured using a single frequency, and
when it is acquired that the dryness degree is a dry state, the fuel cell is humidified such that the water balance is more than that of the first operation state.

5. The method according to claim 4 , wherein
the real part is acquired on the basis of the measured value when the operation state is the first operation state, and the real part is considered to be a value that is smaller than the reference value when the operation state is the second operation state.

Assignees

• Toyota Motor Co Ltd

Inventors

• Shiokawa Satoshi
• Bono Tetsuya
• Hamanoi Osamu

Classifications

• H01M8/04828 Primary

  Humidity; Water content · CPC title

• H01M8/04492

  Humidity; Ambient humidity; Water content · CPC title

• G01R31/3679

  Physics · mapped topic

• H01M8/04126

  Humidifying · CPC title

• H01M8/04664

  Failure or abnormal function · CPC title