Hydrogen supply system for fuel cell and method for controlling the same

This application claims under 35 U.S.C. §119(a) the benefit of Korean Patent Application No. 10-2008-0039149 filed Apr. 28, 2008, the entire contents of which are incorporated herein by reference.

(a) Technical Field

The present invention relates to a hydrogen supply system for a fuel cell and a method for controlling the same. More particularly, the present invention relates to a hydrogen supply system including a plurality of hydrogen tanks, in which an in-tank regulator is mounted on one hydrogen tank and a solenoid valve is mounted on each of the other hydrogen tanks so as to stably supply hydrogen by controlling the solenoid valves during driving, and a method for controlling the same.

(b) Background Art

Generally, a fuel cell system includes a fuel cell stack for generating electrical energy, a fuel (hydrogen) supply system for supplying fuel (hydrogen) to the fuel cell stack, an air supply system for providing oxygen in the air to the fuel cell stack, the oxygen in the air being an oxidizer required for an electrochemical reaction, and a thermal management system for controlling the operating temperature of the fuel cell stack.

Hydrogen compressed to a high pressure of about 350 bar is stored in a hydrogen tank in the fuel supply system. The stored compressed hydrogen is discharged to a high pressure line according to an on/off of a solenoid valve preferably provided at an inlet portion of the hydrogen tank and then supplied to the fuel cell stack after the pressure of the compressed hydrogen is reduced from 350 bar to 10 bar by an external regulator.

Preferably, as a method of storing hydrogen in the hydrogen tank of the fuel cell system, a high pressure compression (350 bar or 700 bar compression) method is generally adopted. Accordingly, a high pressure of 350 bar or 700 bar is always applied to the high pressure line connected to the solenoid valve by the use of the external regulator, thus affecting the durability of the portions to which the high pressure is continuously being applied.

Given the above circumstances, when an in-tank regulator is used instead of the external regulator, it is possible to ensure safety during operation of the system by eliminating the high pressure line, and further it is possible to simplify the system and reduce manufacturing cost.

The in-tank regulator is effective for a single tank system; however, in the case of a multiple tank system including a plurality of tanks, the manufacturing cost of the in-tank regulator is increased since it should be provided at each of the plurality of tanks.

Accordingly, a large-scale single tank system is employed; however, it is necessary to optimally design a space for mounting the large-scale single tank in the vehicle body and chassis, and it is difficult to pack the single tank with peripheral components due to the large volume.

Accordingly, the multiple tank system, in which a plurality of small-scale tanks is mounted, provides a degree of freedom for the vehicle body and chassis design and can be packaged with the peripheral components, as compared with the single tank system. Further, the multiple tank system has a reduced manufacturing cost.

The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

In one aspect, the present invention provides a hydrogen supply system including a plurality of hydrogen tanks, in which an in-tank regulator is preferably mounted only on one hydrogen tank and a solenoid valve is preferably mounted on each of the other hydrogen tanks so that a reduction in manufacturing cost is suitably realized and preferably hydrogen is stably supplied to a fuel cell stack by preferably controlling the solenoid valves during driving, and a method for controlling the same.

In one embodiment, the present invention provides a hydrogen supply system for a fuel cell, the system preferably comprising a plurality of hydrogen tanks, wherein an in-tank regulator is suitably mounted only at an inlet portion of a first hydrogen tank of the plurality of hydrogen tanks and a solenoid valve is preferably mounted at an inlet portion of each of the other hydrogen tanks.

In another embodiment, the present invention provides a method for controlling a hydrogen supply system for a fuel cell, the system preferably including a plurality of hydrogen tanks, and the method comprising: a hydrogen filling step in which high pressure hydrogen is preferably supplied to a high pressure line suitably connecting first to Nth hydrogen tanks to be filled in the first to Nth hydrogen tanks; a hydrogen supply step in which only hydrogen in the first hydrogen tank provided adjacent to a fuel cell stack is preferably supplied to the fuel cell stack during driving of a vehicle; and a hydrogen transfer step in which hydrogen is suitably transferred from the second to Nth hydrogen tanks to the first hydrogen tank during parking or stopping of the vehicle.

In a preferred embodiment, in the hydrogen filling step, a solenoid valve of an in-tank regulator suitably mounted at an inlet portion of the first hydrogen tank and a solenoid valve suitably mounted at an inlet portion of each of the second to Nth hydrogen tanks are all suitably opened by the pressure of high pressure hydrogen so that the high pressure hydrogen is suitably filled in the respective hydrogen tanks.

In another preferred embodiment, in the hydrogen supply step, the solenoid valve of the in-tank regulator suitably mounted at the inlet portion of the first hydrogen tank is preferably controlled to be opened and the solenoid valve suitably mounted at the inlet portion of each of the second to Nth hydrogen tanks is preferably controlled to be suitably closed so that only the hydrogen in the first hydrogen tank is supplied to the fuel cell stack.

In still another preferred embodiment, in the hydrogen transfer step, the solenoid valve of the in-tank regulator suitably mounted at the inlet portion of the first hydrogen tank is preferably controlled to be suitably closed and the solenoid valve suitably mounted at the inlet portion of each of the second to Nth hydrogen tanks is preferably controlled to be suitably opened so that the hydrogen in the second to Nth hydrogen tanks is transferred and filled in the first hydrogen tank.

In yet another preferred embodiment, when the pressure of the first to Nth hydrogen tanks is suitably reduced to a minimum operating pressure, the solenoid valve of the in-tank regulator of the first hydrogen tank and the solenoid valves of the second to Nth hydrogen tanks are preferably controlled to be all opened so that residual hydrogen in the respective hydrogen tanks is used.

It is understood that the term “vehicle” or “vehicular” or other similar term as used herein is inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g. fuels derived from resources other than petroleum).