Method to detect fuel cell gas leak

Patent metadata

Field	Value
Publication number	US-11043682-B2
Application number	US-201715401798-A
Country	US
Kind code	B2
Filing date	Jan 9, 2017
Priority date	Jan 9, 2017
Publication date	Jun 22, 2021
Grant date	Jun 22, 2021

Abstract

A method for determining if there is a gas leak in an anode volume of a fuel cell stack in a fuel cell system. The method includes determining a total amount of gas loss in the anode volume of the fuel cell stack during a predetermined period of time, and monitoring losses of the gas from the anode volume during the predetermined period of time, such as reaction losses, crossover losses and overboard losses. The method also includes subtracting the losses of the gas from the total amount of gas loss to get an anode leak loss and comparing the anode leak loss to a predetermined threshold to identify a hydrogen gas leak.

First claim

What is claimed is:

1. A method for determining if there is a hydrogen gas leak in an anode volume of a fuel cell stack in a fuel cell system, said method comprising:
determining that the fuel cell system is in a leak detection condition;
determining an initial amount of gas in the anode volume at a start time of a predetermined time period during the leak detection condition;
determining a crossover loss of the hydrogen gas from the anode volume of the fuel cell stack during the predetermined time period as a result of permeation through cell membranes in the fuel cell stack;
determining an overboard loss of the hydrogen gas from the anode volume of the fuel cell stack during the predetermined time period as a result of permeation through one or more of a gasket, a valve, and a seal arranged in the fuel cell stack;
determining a reaction loss of the hydrogen gas from the anode volume of the fuel cell stack during the predetermined time period as a result of an electro-chemical reaction from a load on or to the fuel cell stack;
adding the crossover, overboard and reaction losses to get an added loss;
determining a final amount of gas in the anode volume at an end time of the predetermined time period;
determining the total gas loss from the anode volume of the fuel cell stack by subtracting the final amount of gas from the initial amount of gas;
subtracting the added loss from the total gas loss to get an anode leak loss; and
comparing the anode leak loss to a predetermined threshold to identify a hydrogen gas leak.

2. The method according to claim 1 wherein determining a crossover loss, determining an overboard loss and determining a reaction loss all include using pressure and electrical current measurements in the anode volume of the fuel cell stack.

3. The method according to claim 1 wherein determining an overboard loss includes determining an overboard loss as a result of permeation through gaskets, sub-gaskets, seals and valves in the fuel cell stack.

4. The method according to claim 1 wherein determining a crossover loss and an overboard loss includes considering an age of the membranes and the one or more of the gasket, the valve, and the seal arranged in the fuel cell stack.

5. The method according to claim 1 wherein determining that the fuel cell system is in a leak detection condition includes determining that a zero net power is requested to the fuel cell system.

6. The method according to claim 5 wherein determining that the fuel cell system is in a leak detection condition includes determining that the fuel cell system is in a shut-down, start-up, wake-up or stand-by mode.

7. The method according to claim 1 wherein determining that the fuel cell system is in a leak detection condition includes determining that a power sink is requested to the fuel cell system.

8. The method according to claim 1 wherein the method uses the equation:

n

An
,
leak

=

n

An
,
tot

-

∑

t
i

t
f

⁢

(

n
.

xovr

+

n
.

ovrbrd

+

n
.

reaction

)

⁢

t
step

where n An,leak is the anode leak loss in moles, n An,tot is the total gas loss in moles, {dot over (n)} xovr is the crossover loss in moles/sec, {dot over (n)} ovrbrd is the overboard loss in moles/sec, {dot over (n)} reaction is the reaction loss in moles/sec, t i is the start time of the predetermined time period, t f is the end time of the predetermined time period, and t step defines a calculation time step during the predetermined time step.

9. The method according to claim 1 wherein determining an initial amount of gas and a final amount of gas includes determining the number of moles of the gas.

10. A method for determining if there is a gas leak exceeding a predetermined threshold in an anode volume of a fuel cell stack in a fuel cell system, said method comprising:
determining a first total concentration of gas in the anode volume of the fuel cell stack at a first predetermined point in time;
monitoring losses of the gas from the anode volume of the fuel cell stack from the first predetermined point in time to a second predetermined point in time to obtain a stack gas loss;
determining a second total concentration of gas in the anode volume of the fuel cell stack at the second predetermined point in time;
subtracting the first and second total concentration of gas to get a total gas loss; and
comparing the total gas loss to the stack gas loss to determine if there is a gas leak exceeding a predetermined threshold.

11. The method according to claim 10 wherein monitoring losses of the gas includes determining a crossover loss of the gas as a result of permeation through membranes in the fuel cell stack, determining an overboard loss of the gas as a result of permeation through gaskets, sub-gaskets, seals and valves in the fuel cell stack, and determining a reaction loss of the gas as a result of an electro-chemical reaction from a load on or a source to the stack.

12. The method according to claim 11 wherein the method includes using the equation:

n

An
,
leak

=

n

An
,
tot

-

∑

t
i

t
f

⁢

(

n
.

xovr

Assignees

• Gm Global Tech Operations Llc

Inventors

• Gagliardo Jeffrey J
• Pace Stephen D

Classifications

• H01M8/04223

  during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells · CPC title

• H01M8/04388

  of anode reactants at the inlet or inside the fuel cell · CPC title

• H01M8/04574

  Current · CPC title

• H01M8/04402

  of anode exhausts · CPC title

• Y02E60/50

  Fuel cells · CPC title