Method for Starting a Fuel Cell

Patent metadata

Field	Value
Publication number	US-2020388866-A1
Application number	US-201816954707-A
Country	US
Kind code	A1
Filing date	Nov 29, 2018
Priority date	Dec 18, 2017
Publication date	Dec 10, 2020
Grant date	—

Abstract

A method for starting a fuel cell in a fuel cell system, at temperatures below the freezing point of water, includes, in a first step, that the hydrogen concentration in the anode is increased; after which, in a second step, an anode pressure is increased for a fixed period of time, and while air is supplied to the cathode, the maximum possible current is drawn from the fuel cell, and after which, in a third step, the fuel cell is switched in a load-free manner and the anode pressure is reduced. After the third step, the second step and the third step are repeated successively until a sufficient performance of the fuel cell for its normal operation is reached.

First claim

1 .- 10 . (canceled)

11 . A method for starting a fuel cell in a fuel cell system at a temperature below a freezing point of water, comprising the steps of:
increasing a hydrogen concentration in an anode in a first step; following the first step, increasing an anode pressure for a fixed period of time and, while air is supplied to the cathode, drawing a maximum possible current from the fuel cell in a second step; following the second step, switching the fuel cell in a load-free manner and reducing the anode pressure in a third step; and following the third step, repeating the second step and the third step consecutively until the fuel cell reaches a sufficient performance level for its normal operation.

12 . The method according to claim 11 , wherein a change of the anode pressure is achieved by a combined control or regulation of a hydrogen dosage and a discharge valve for media from the anode.

13 . The method according to claim 12 , wherein, before the first step, the anode pressure is increased and a function of the discharge valve is checked.

14 . The method according to claim 12 , wherein the increasing of the hydrogen concentration in the first step is performed with the discharge valve open until a permissible emission limit for hydrogen in an exhaust gas is reached.

15 . The method according to claim 11 , wherein the hydrogen concentration increased in the first step to more than 90%.

16 . The method according to claim 11 , wherein, during the third step, no hydrogen is supplied into the anode.

17 . The method according to claim 11 , wherein, during the third step, air supplied to the cathode is reduced compared to the air supplied to the cathode in the second step.

18 . The method according to claim 11 , wherein, during the first step, air supplied to the cathode takes place at a lower level than during the second step.

19 . The method according to claim 13 , wherein, while the anode pressure is increased before the first step, no air is supplied to the cathode.

20 . The method according to claim 11 , wherein dosing of hydrogen into the anode takes place in a pulsating manner.

Assignees

• Daimler Ag

Inventors

• Pastor Nigorra Pere Antoni
• Schmalzriedt Sven
• Fellows Richard
• Iwan Laura

Classifications

• H01M8/04253 Primary

  Means for solving freezing problems · CPC title

• H01M8/0491

  of fuel cell stacks · CPC title

• H01M8/04302

  applied during start-up · CPC title

• H01M8/04753

  of fuel cell reactants · CPC title

• H01M2250/20

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