US20120145280A1

US20120145280A1 - Apparatus for injecting coolant for fuel cell vehicle

Info

Publication number: US20120145280A1
Application number: US13/189,686
Authority: US
Inventors: Chi Myung Kim; Haengjin Ko; Seong Kyun Kim; Seung Yong Lee; Gi Young Nam; Yun Seok Kim
Original assignee: Hyundai Motor Co
Current assignee: Hyundai Motor Co
Priority date: 2010-12-08
Filing date: 2011-07-25
Publication date: 2012-06-14
Also published as: KR20120063918A; KR101209746B1

Abstract

An apparatus for injecting a coolant for a fuel cell vehicle is provided. More specifically, a coolant tank stores a coolant and a coolant pump, disposed in a coolant supply line connecting the coolant tank and the stack cooling loop is configured to pressure-transfer the coolant to the stack cooling loop, and circulating the coolant, which has passed through the stack cooling loop, to the coolant tank. A bubble elimination unit, disposed at a rear stage of the coolant pump in the coolant supply line, eliminates the bubbles in the fuel cell stack through vibration. This bubble elimination unit may be configured as an ultrasonic wave excitor for exciting the stack cooling loop with ultrasonic waves.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2010-0125096 filed in the Korean Intellectual Property Office on Dec. 8, 2010, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

(a) Field of the Invention
The present invention relates to a refrigerating system of a fuel cell vehicle and, more particularly, to an apparatus for injecting coolant into a stack cooling loop, and a water/heat management system of a fuel cell vehicle.
(b) Description of the Related Art
A fuel cell vehicle including a fuel cell system produces electricity by supplying hydrogen used as fuel to a fuel cell stack, and operates an electric motor with the electricity produced via the fuel cell stack to drive a vehicle. Thus, a fuel cell system is a sort of a power generation system for directly electrochemically converting chemical energy of fuel (hydrogen) into electric energy within a fuel cell stack, rather than changing the chemical energy into heat through combustion.
The fuel cell stack is formed by stacking tens to hundreds of unit fuel cells together. Each fuel cell is generally comprised of a membrane electrode assembly (MEA), a gasket, a separator, and the like, to obtain a desired output. Fuel cell stacks generate a large quantity of heat along with a fuel cell reaction, so the fuel cell system requires a cooling system for cooling the stack.
The cooling system for a fuel cell vehicle typically uses antifreeze as a coolant via a coolant injection process is often performed during the manufacture of a vehicle. In general, in order to inject the coolant, a method of vacuumizing an overall coolant line and injecting a pressurized coolant is employed. The reason for vacuumizing the entire coolant line is to prevent the presence of bubbles in the interior of the cooling system. If bubbles (air) exist in the interior of the cooling system, the coolant overflows when the vehicle is driven, causing a shortage of the coolant as a result, thus, increasing the possibility of overheating.
In particular, when bubbles exist in the interior of a fuel cell stack of the fuel cell vehicle, stack efficiency and cooling performance are degraded due to an increase in a local temperature, and the fuel cell may be damaged as a result. Thus, elimination of the bubbles in injecting the coolant is requisite.
However, in the vehicle fuel cell system, a stack is fabricated by stacking hundreds to thousands of sheets of components, and gaskets are used for air-tightness, so when it is exposed to the vacuum state, the air tightness can be hard to maintain, and in a worst-case scenario, the separator may be damaged. Thus, in fuel cell vehicles, the use of a coolant injection apparatus for an engine vehicle requires extreme caution.
Accordingly, in an effort to improve this, a press circulation type coolant injection apparatus for circulatively charging a coolant to the interior of a flow path of a cooling system by using a coolant circulating apparatus has been proposed. In this case, however, it is not easy to eliminate bubbles from the interior of the stack. In order to eliminate bubbles from the interior of the stack, the coolant must be circulated at a very high speed, resulting in an excessive increase in the pressure in the cooling system which negatively affects the air-tightness of the stack and may damage components such as the separator, or the like.
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.

SUMMARY OF THE INVENTION

The present invention provides an apparatus for injecting a coolant for a fuel cell vehicle which eliminates bubbles from the interior of a fuel cell stack in injecting a coolant to a stack coolant loop.
An exemplary embodiment of the present invention provides an apparatus for injecting a coolant to a stack cooling loop for cooling a fuel cell stack in a fuel cell vehicle. The apparatus includes a coolant tank configured to store a coolant; a coolant pump formed in a coolant supply line connecting the coolant tank and the stack cooling loop to pressure-transfer the coolant to the stack cooling loop, and circulating the coolant, which has passed through the stack cooling loop, to the coolant tank; and a bubble elimination unit disposed at a rear stage of the coolant pump in the coolant supply line and configured to eliminate bubbles in the fuel cell stack through vibration, wherein the bubble elimination unit is configured as an ultrasonic wave excitor for exciting the stack cooling loop with ultrasonic waves.
In the apparatus for injecting a coolant for a fuel cell vehicle, the ultraviolet excitor may be configured as a piezoelectric element or in a magnetic manner and the stack cooling loop and the coolant tank may be connected through a first coolant circulation line. Additionally, the first coolant circulation line may supply bubbles, which are eliminated from the fuel cell stack, to the coolant tank.
In the exemplary apparatus for injecting a coolant for a fuel cell vehicle, the coolant tank may include a first outlet connected to the coolant supply line, a first inlet connected to the first coolant circulation line, and a bubble outlet for allowing the bubbles to be exhausted therethrough to the outside. A filter unit may be installed at the rear stage of the coolant pump in the coolant supply line and a second outlet and a second inlet may be formed at the cooling tank. The second outlet and the second inlet may be interconnected through a second coolant circulation line.
In the apparatus for injecting a coolant for a fuel cell vehicle, a filter pump and a filter unit may be installed in the second coolant circulation line. The filter unit may be configured as an ion eliminator charged with an ion exchange resin.
According to an exemplary embodiment of the present invention, when the coolant is injected into the stack cooling loop, bubbles within the fuel cell stack can be easily eliminated through the ultraviolet excitor. Thus, in the present exemplary embodiment, the elimination of the bubbles present in the interior of the stack prevent an increase in a local temperature of the stack otherwise caused by bubbles or air in the line, thus improving operation efficiency and cooling performance of the stack, and preventing damage to the fuel cell otherwise caused by an increase in the local temperature.
In addition, in the present exemplary embodiment, unlike the related art in which bubbles are eliminated from the interior of the stack by injecting the coolant with an excessive amount of pressure, bubbles are eliminated through a simple excitation via ultraviolet waves without applying pressure to the coolant, and thus, the air-tightness of the stack cannot be broken otherwise by the excessive pressure of the coolant and the components can be prevented from being damaged.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings, which are given by illustration only, and thus are not limiting to the present invention.

FIG. 1 is a schematic block diagram of an apparatus for injecting a coolant for a fuel cell vehicle according to an exemplary embodiment of the present invention.

FIG. 2 is a schematic block diagram of an apparatus for injecting a coolant for a fuel cell vehicle according to another exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.
In order to clarify the present invention, parts that are not connected with the description will be omitted, and the same elements or equivalents are referred to as the same reference numerals throughout the specification.
The size and thickness of each element are arbitrarily shown in the drawings, and the present invention is not necessarily limited thereto, and in the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity.
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). As referred to herein, a hybrid vehicle is a vehicle that has two or more sources of power, for example both gasoline-powered and electric-powered vehicles.
FIG. 1 is a schematic block diagram of an apparatus for injecting a coolant for a fuel cell vehicle according to an exemplary embodiment of the present invention.
With reference to FIG. 1, an apparatus 100 for injecting a coolant for a fuel cell vehicle according to an exemplary embodiment of the present invention serves to inject a coolant into a stack cooling loop 1, a system for cooling a fuel cell stack as a power generation module of a fuel cell vehicle. Here, the stack cooling loop 1 is provided as a thermal/water management system (TMS) which removes heat generated from the fuel cell stack, controls an operation temperature of the stack, and performs one or more water management functions. The thermal/water management system, includes a radiator, a cooling fan, a heater, a controller, a water pump, or the like, is widely known in the art, so a detailed description of a configuration thereof will be omitted.
Meanwhile, the foregoing fuel cell stack is configured as an electrical generation aggregate in which unit fuel cells generating electrical energy according to an electrochemical reaction between fuel and an oxidizing agent are continuously arranged. In this case, heat is generated when the fuel cell stack generates electrical energy, so a coolant passage allowing the coolant to be circulated therealong is configured between the unit fuel cells as mentioned above.
The apparatus 100 for injecting a coolant for a fuel cell vehicle according to the present exemplary embodiment has a structure in which bubbles in the interior of the fuel cell stack are easily eliminated when the coolant is injected into the stack cooling loop 1. To this end, the apparatus 100 for injecting a coolant for a fuel cell vehicle according to the present exemplary embodiment includes a coolant tank 10, a coolant pump 40, and a bubble elimination unit 80. These elements will now be described.
In the present exemplary embodiment, the coolant tank 10 may be a water tank storing the coolant, which is configured to supply the coolant to the stack cooling loop 1 and allow the coolant, which has passed through the stack cooling loop 1, to flow thereinto. To this end, the coolant tank 10 includes a first outlet 11 allowing the coolant to be exhaust therethrough, and a first inlet 13 allowing the coolant, which has passed through the stack cooling loop 1, to be introduced therethrough.
The first outlet 11, serves to allow the coolant to be exhausted therethrough to the fuel cell stack, e.g., the stack cooling loop 1, may be connected back to the stack cooling loop 1 through a coolant supply line 21. On the other hand, the first inlet 13, which serves to allow the coolant, which has passed through the stack cooling loop 1, to be re-circulated to the coolant tank 10, to be connected to the stack cooling loop 1 through a first coolant circulation line 23.
Meanwhile, a bubble outlet 17, allowing bubbles to be exhausted therethrough from the interior of the fuel cell stack which has been eliminated by the bubble elimination unit 80 (to be described), is formed at the coolant tank 10, and in this case, the bubble outlet 17 may be formed on an upper/top end portion of the coolant tank 10.
In the present exemplary embodiment, the coolant pump 40 pressure-transfers the coolant stored in the coolant tank 10 to the stack cooling loop 1 through the coolant supply line 21. The coolant pump 40 serves to forcibly circulate the coolant, which has passed through the stack cooling loop 1, to the coolant tank 10 through the first coolant circulation line 23. The coolant pump 40 is installed in the coolant supply line 21, and since it is configured as a known water pump commonly employed in a cooling system in the art, a detailed description thereof will be omitted.
The filter unit 60 may be configured at a rear stage of the coolant pump 40 in the coolant supply line 21. The filter unit 60 is configured as an ion eliminator charged with a ion exchange resin. Before the coolant is supplied to the stack cooling loop 1, the filter unit 60 eliminates metal ions from the coolant so that the coolant has an electric conductivity higher than the level required for the fuel cell vehicle. The bubble elimination unit 80 then eliminates bubbles from the interior of the fuel cell stack through vibration when the coolant is injected into the stack cooling loop 1. The bubble elimination unit 80 may be configured as an ultrasonic wave excitor 81 for exciting the stack cooling loop 1 with ultrasonic waves by using the coolant supplied to the fuel cell stack of the stack cooling loop 1. The ultrasonic wave excitor 81 may be formed at a rear stage/subsequent to the filter unit 60 in the coolant supply line 21.
When the coolant is injected into the stack cooling loop 1, the ultrasonic wave excitor 81 generates ultrasonic waves to oscillate the coolant with the ultrasonic waves to excite the coolant passage in the fuel cell stack, thus eliminating the bubbles in the interior of the fuel cell stack. The ultrasonic wave excitor 81 is configured in a magnetic manner or piezoelectric element manner widely known in the art, so a detailed description thereof will be omitted.
Here, the bubbles eliminated from the coolant passage of the fuel cell stack according to the excitation by the ultrasonic waves are supplied along with the coolant to the coolant tank 10 through the first coolant circulation line 23 as mentioned above. Namely, the bubbles eliminated from the coolant passage of the fuel cell stack are supplied to the coolant tank 10 along with the coolant through the first coolant circulation line 23 by the coolant pump 40, and air generated from the eliminated bubbles can be discharged to the outside through the bubble outlet 17 of the coolant tank 10.
In FIG. 1, reference numeral 90 denotes a supply valve formed between the filter unit 60 and the ultrasonic wave excitor 81 in the coolant supply line 21 in order to selectively prevent a supply of the coolant from being injected into the stack cooling loop 1.
Thus, in the apparatus 100 for injecting a coolant for a fuel cell vehicle according to an exemplary embodiment of the present invention configured as described above, the coolant of the coolant tank 10 is exhausted through the first outlet 11 by operating the coolant pump 40. The coolant passes through the filter unit 60 of the coolant supply line 21, and in this case, in the present exemplary embodiment, metal ions of the coolant are removed by the ion exchange resin of the filter unit 60, whereby the electrical conductivity of the coolant can be maintained at a level higher than what is required for the fuel cell vehicle. Through the foregoing process, the coolant is injected into the stack cooling loop 1, and in this process, the ultrasonic wave excitor 81 according to the present exemplary embodiment generates ultrasonic waves and oscillates the coolant with the ultrasonic waves to thus eliminate bubbles in the interior of the fuel cell stack.
Meanwhile, in the present exemplary embodiment, the coolant, which has passed through the stack cooling loop 1, is circulated to the coolant tank 10 along (or through) the first coolant circulation line 23 through a pumping operation performed by the coolant pump 40. In this process, as mentioned above, the bubbles, which have been removed from the interior of the fuel cell stack by the ultrasonic wave excitor 81, are supplied along with the coolant to the coolant tank 10 through the first coolant circulation line 23. And then, air generated from the bubbles is exhausted from the interior of the coolant tank 10 to the outside through the bubble outlet 17.
As described above, in the apparatus 100 for injecting a coolant for a fuel cell vehicle according to the present exemplary embodiment of the present invention, when the coolant is injected into the stack cooling loop 1, bubbles in the interior of the fuel cell stack can be easily eliminated by the ultrasonic wave excitor 81. Thus, in the present exemplary embodiment, since the bubbles present in the interior of the stack are eliminated, an increase in the local temperature of the stack otherwise created by the bubbles can be prevented, thus enhancing the operation efficiency and cooling performance of the stack, and preventing damage to the fuel cell caused otherwise due to the increase in the local temperature.
In addition, in the present exemplary embodiment, unlike the related art in which bubbles are eliminated from the interior of the stack by injecting the coolant with an excessive pressure, bubbles are eliminated through simple excitation by ultraviolet waves without applying pressure to the coolant, and thus, the air-tightness of the stack cannot be broken otherwise by the excessive pressure of the coolant and the components can be prevented from being damaged.
FIG. 2 is a schematic block diagram of an apparatus for injecting a coolant for a fuel cell vehicle according to another exemplary embodiment of the present invention.
With reference to FIG. 2, unlike the apparatus 100 for injecting a coolant for a fuel cell vehicle according to the previous exemplary embodiment in FIG. 1, in an apparatus 200 for injecting a coolant for a fuel cell vehicle according to another exemplary embodiment of the present invention, the filter unit 160 is not mounted in the coolant supply line 121, and a coolant circulation path is configured at a coolant tank 110 and the filter 160 is disposed within the coolant circulation path.
To this end, in the present exemplary embodiment, a first outlet 111, a first inlet 113, an air outlet 117, a second outlet 112, and a second inlet 114 are formed at the coolant tank 110. Here, the second outlet 112 and the second inlet 114 are connected through the second coolant circulation line 124 and the foregoing filter unit 160 is installed in the second coolant circulation line 124. In this case, a filter pump 126 is installed at a front stage of the filter unit 160 in the second coolant circulation line 124. The filter pump 126 pressure-transfers a coolant stored in the coolant tank 110 to the filter unit 160 to allow the coolant to be circulated to the coolant tank 110 through the second coolant circulation line 124.
Accordingly, the coolant stored in the coolant tank 110 is exhausted through the second outlet 112 of the coolant tank 110 through the pumping operation performed by the filter pump 126, flows along the second coolant circulation line 124, and is circulated to the interior of the coolant tank 110 through the second inlet 114. In this process, the coolant passes through the filter unit 160 in which metal ions of the coolant are removed by the ion exchange resin, and the metal ion-free coolant is recirculated to the coolant tank 110.
Other configurations of the apparatus 200 for injecting a coolant for a fuel cell vehicle according to the present exemplary embodiment, namely, a configuration of an ultrasonic wave excitor 181 of a bubble elimination unit 180, a structure for injecting the coolant to the stack cooling loop 1, a coolant circulation structure through a coolant pump 140 and a first coolant circulation line 123, and the like, are the same as those of the former exemplary embodiment, so a detailed description thereof will be omitted.
While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

DESCRIPTION OF SYMBOLS

- 1 . . . stack cooling loop
- 10, 110 . . . coolant tank
- 11, 111 . . . first outlet
- 13, 113 . . . first inlet
- 17 . . . bubble outlet
- 21, 121 . . . coolant supply line
- 23 . . . first coolant circulation line
- 40 . . . coolant pump
- 60, 160 . . . filter unit
- 80 . . . bubble elimination unit
- 81 . . . ultrasonic wave excitor
- 112 . . . second outlet
- 114 . . . second inlet
- 124 . . . second coolant circulation line
- 126 . . . filter pump

Claims

1. An apparatus for injecting a coolant into a stack cooling loop for cooling a fuel cell stack in a fuel cell vehicle, the apparatus comprising:

a coolant tank storing a coolant;

a coolant pump formed in a coolant supply line configured to connect the coolant tank and the stack cooling loop to pressure-transfer the coolant to the stack cooling loop, and circulate the coolant, which has passed through the stack cooling loop, to the coolant tank; and

a bubble elimination unit disposed at a rear stage of the coolant pump in the coolant supply line, the bubble elimination unit configured to eliminate bubbles in the fuel cell stack through vibration, wherein the bubble elimination unit is configured as an ultrasonic wave excitor for exciting the stack cooling loop with ultrasonic waves.

2. The apparatus of claim 1, wherein the ultraviolet excitor is configured as a piezoelectric element or in a magnetic manner.

3. The apparatus of claim 1, wherein the stack cooling loop and the coolant tank are connected through a first coolant circulation line, and the first coolant circulation line supplies bubbles, which are eliminated from the fuel cell stack, to the coolant tank.

4. The apparatus of claim 3, wherein the coolant tank comprises a first outlet connected to the coolant supply line, a first inlet connected to the first coolant circulation line, and a bubble outlet for allowing the bubbles to be exhausted therethrough to the outside.

5. The apparatus of claim 1, wherein a filter unit is installed at the rear stage of the coolant pump in the coolant supply line.

6. The apparatus of claim 5, wherein the filter unit is configured as an ion eliminator charged with an ion exchange resin.

7. The apparatus of claim 1, wherein a second outlet and a second inlet are formed at the cooling tank, the second outlet and the second inlet interconnected through a second coolant circulation line, and a filter pump and a filter unit installed within the second coolant circulation line.

8. The apparatus of claim 7, wherein the filter unit is configured as an ion eliminator charged with an ion exchange resin.

9. A method for injecting a coolant into a stack cooling loop for cooling a fuel cell stack in a fuel cell vehicle, the apparatus comprising:

storing a coolant in a tank

pressure-transferring, by a first pump through a coolant supply line, the coolant to the stack cooling loop, and circulating the coolant by connecting the coolant tank and the stack cooling loop, the coolant having already passed through the stack cooling loop, to the coolant tank, wherein the coolant pump is formed in the coolant supply line;

eliminating bubbles in the fuel cell stack through vibration by a bubble elimination unit disposed at a rear stage of the coolant pump in the coolant supply line, wherein the bubble elimination unit is configured as an ultrasonic wave excitor for exciting the stack cooling loop with ultrasonic waves.

10. The method of claim 9, wherein the ultraviolet excitor is configured as a piezoelectric element or in a magnetic manner.

11. The method of claim 9, further comprising supplying bubbles through a first coolant circulation line which are eliminated from the fuel cell stack, to the coolant tank wherein the stack cooling loop and the coolant tank are connected through the first coolant circulation line.

12. The method of claim 11, wherein the coolant tank includes a first outlet connected to the coolant supply line, a first inlet connected to the first coolant circulation line, and a bubble outlet for allowing the bubbles to be exhausted therethrough to the outside.

13. The method of claim 9, wherein a filter unit is installed at the rear stage of the coolant pump in the coolant supply line.

14. The method of claim 13, wherein the filter unit is configured as an ion eliminator charged with an ion exchange resin.

15. The method of claim 9, wherein a second outlet and a second inlet are formed at the cooling tank, the second outlet and the second inlet interconnected through a second coolant circulation line, and a filter pump and a filter unit installed within the second coolant circulation line.

16. The apparatus of claim 15, wherein the filter unit is configured as an ion eliminator charged with an ion exchange resin.