JP2016072183A - Centrifugal water separation device for fuel battery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal separation device for a fuel battery system that removes water from an anode recirculation loop of the fuel battery system.SOLUTION: A separation device 100 has a first part 104 and a second part 102 which form a chamber 110. The first part has an inner wall and an end wall which are continuous with each other, a suction pipe 122 is coupled to the inner wall, and a liquid drain pipe 126 is coupled to the end wall. The second part has an end wall, and a discharge pipe 130 which extends to the chamber so as to form a flow path between the discharge pipe 130 and the inner wall of the first part. The separation device contains a first end portion and a second end portion which are coupled to each other through a side wall to define the boundary of the chamber. The suction pipe is brought into contact with and coupled to the side wall. The discharge pipe is coupled to the first end portion, and extends to the chamber so as to form a flow path between the discharge pipe and the side wall. The liquid drain pipe is coupled to the second end portion.SELECTED DRAWING: Figure 3

Description

  Various embodiments relate to an apparatus for removing water from a fuel cell system.

  During operation of the fuel cell, by-products such as water and nitrogen produced and unconsumed hydrogen may occur on the anode side of the fuel cell stack. In some known systems, the water accumulation and nitrogen accumulation produced are controlled in an attempt to avoid fuel cell performance degradation and / or fuel cell system shutdown. One known approach is to release water and nitrogen through a flow path downstream of the fuel cell stack. By-products can be recycled so that unconsumed hydrogen returns to the anode side of the fuel cell stack. Recirculation can also be utilized to wet the anode side to promote efficient chemical conversion and to prolong cell membrane life. However, liquid water, such as water droplets, in the recirculation flow may have to be removed to avoid water blockages in the fuel cell stack flow field flow path or ejector.

  Traditional water separation devices have channels, screens and / or meshes that place water droplets on the impact stream for water removal. These devices can have a high water removal efficiency, for example reaching 99%. However, these conventional device designs cause a relatively large pressure drop on the system relative to the volume of the device.

  For ejector-based fuel cell systems with passive recirculation loops, it can be important to minimize the pressure drop through the anode loop of the fuel cell system. The ejector is a momentum transmission device and the passive recirculation flow it causes is one function of the compression work done by the ejector. The pressure drop in the anode loop can increase the compression work for the ejector and limit the recirculation flow. The dominant pressure drop in the anode loop is caused by the fuel cell stack, and the pressure drop along other components such as the water separator is minimized in order for the ejector and fuel cell to function properly. There is a need. In addition, since it is preferred that some humidity be in the recirculation flow, the high efficiency of conventional separators can result in over-degrading humidity and degrading fuel cell performance and life.

  According to one embodiment, a fuel cell system includes a fuel cell stack and a separation device in fluid communication with the fuel cell stack. The separation device includes a first and a second end coupled by a side wall to form a chamber, a suction pipe coupled in contact with the side wall, and a flow path between the first end and the side wall. A discharge pipe extending into the chamber to form a liquid drain pipe coupled to the second end.

  According to another embodiment, a liquid separator for a fuel cell system comprises first and second ends that are joined by side walls to form a chamber. A suction pipe is coupled in contact with the side wall. A discharge tube is coupled to the first end and extends into the chamber to form a flow path between the discharge tube. A liquid drain tube is coupled to the second end.

  According to yet another embodiment, a fuel cell system includes a fuel cell stack and a separation device in fluid communication with the fuel cell stack. The separation device has a first part and a second part forming a chamber. The first portion has a continuous inner wall and an end wall, a suction pipe is coupled to the inner wall, and a liquid drain pipe is coupled to the end wall. The second portion has a discharge tube extending to the chamber so as to form a flow path between the end wall and the inner wall of the first portion.

  Various embodiments of the present disclosure relate to non-limiting advantages. For example, realizing a small pressure drop in the separator allows the use of a passive recirculation loop on the anode side of the fuel cell. A small pressure drop occurs in the separator due to smooth tangential fluid flow into the separator and by not using additional mesh members in the gas phase fluid flow path within the separator. The separator is designed to remove large drops of water from the fluid stream while leaving water vapor and small sized drops. Thus, the separation device does not have very high efficiency for total water removal. This is acceptable for fuel cell applications because humidity is required on both the anode and cathode sides for the fuel cell to function properly. The separator must remove a sufficient amount of droplets of a size that can cause overflow of the stack anode flow field. Since the flow at the anode is mixed with a fresh fresh hydrogen supply prior to entry into the stack, small droplets can be vaporized prior to reaching the stack. In addition, the stack module can tolerate the intake of a certain amount of liquid water without reducing cell voltage stability. This amount is usually in the range of 5-30 cc / min. The design of the separation device provides a small, dense and easy to manufacture device that allows its use in applications such as fuel cell systems in vehicles where mounting, weight and cost are current concerns. In addition, the structure and assembly of the separator is designed to be compatible with hydrogen molecules in the fluid flow, such as downstream of the anode side of the fuel cell stack.

1 is a schematic view of a fuel cell system according to one embodiment. It is a perspective view of the water separator which concerns on one embodiment used with the fuel cell of FIG. FIG. 3 is a partial cross-sectional perspective view of the water separator of FIG. 2. It is the graph which compared the pressure drop of the conventional separator and the separator of FIG. 2 in various mass flow rates.

  Detailed embodiments of the present invention are appropriately disclosed herein. However, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various alternative forms. The drawings are not necessarily to scale, and some features may be exaggerated or minimized to present specific components in detail. Accordingly, specific structural and functional details disclosed herein are not to be construed as limiting, but merely as representative criteria for teaching those skilled in the art to make various use of the present invention. belongs to. The notation of the component in the chemical formula refers to a component when added to any combination specified by the notation, and does not necessarily exclude the chemical interaction between the components of the mixture once mixed.

  FIG. 1 schematically illustrates a fuel cell system 10 as a process flow diagram according to at least one embodiment. For example, the fuel cell system 10 can be used in a vehicle to provide power to operate an electric motor to drive the vehicle or achieve other vehicle functions. The fuel cell system 10 may be a conventionally known Proton Exchange Membrane Fuel Cell (PEMFC).

  The fuel cell system 10 includes a fuel cell stack 12. The stack 12 has an anode side 14, a cathode side 16, and a membrane 18 therebetween. The fuel cell system 10 is in electrical communication with, for example, a high voltage bus 20 or a traction battery and supplies energy. The fuel cell stack 12 may further include a cooling loop (not shown).

  During operation of the fuel cell system 10, generated water, residual fuel such as hydrogen, and by-products such as nitrogen may accumulate on the anode side 14 of the fuel cell stack 12. Attempts have been made to remove liquid generated water and by-products and to recycle residual hydrogen and water vapor. One approach is to collect these components with a separator 36 downstream of the fuel cell stack 12, separate at least a portion of liquid water and / or nitrogen, and leave the remainder via a return channel in a recirculation loop. Is returned to the fuel cell stack 12.

  An initial fuel source 22 is coupled to the anode side 14 of the fuel cell stack 12 as an initial hydrogen source. A non-limiting example of the initial hydrogen source 22 is a high pressure hydrogen storage tank or hydride storage device. The hydrogen source 22 is coupled to one or more ejectors 24. The ejector 24 has a nozzle 26 that supplies hydrogen to the concentrated portion of the concentrated / branched nozzle 28. The branch of the nozzle 28 is coupled to the input 30 on the anode side 14.

  The output 32 on the anode side 14 is coupled to a passive recirculation loop 34. In general, excess hydrogen gas is supplied to the anode side 14 to ensure that there is sufficient available hydrogen for all cells in the stack 12. In other words, hydrogen is supplied to the fuel cell stack 12 at a stoichiometric ratio greater than 1, ie, a fuel rich ratio with respect to precise electrochemical requirements. A recirculation loop 34 is provided so that excess hydrogen not used on the anode side 14 can be returned to the input 30 and utilized without being discarded.

  In addition, the accumulated liquid and vapor phase water is the output on the anode side 14. The anode side 14 requires humidification for efficient chemical conversion and for extended membrane life. A recirculation loop 34 may be utilized to supply water to humidify the hydrogen gas upstream of the input 30 on the anode side 14.

  The recirculation loop 34 has a separator 36 or a dehydrator. Separator 36 receives a flow or fluid mixture of hydrogen gas, nitrogen gas and water from output 32 on anode side 14. The water may be a mixed phase and includes both liquid and gas phase water. Separator 36 removes at least a portion of the liquid phase water, which is discharged from the separator via drain line 38. At least some of the nitrogen gas, hydrogen gas, and vapor phase water may exit the drain line 38 and pass through the control valve 39 during, for example, the purification process of the fuel cell stack 12. Residual fluid in separator 36 exits through a flow path 40 coupled to ejector 24 in recirculation loop 34. The fluid in the flow path 40 is supplied to the concentrated portion of the concentrated / branched nozzle 28 where it is mixed with hydrogen flowing from the nozzle 26 and the hydrogen source 22.

  Liquid water can be removed from the anode side 14 by the separator 36 to prevent water blockage in the flow paths and cells on the anode side 14. A water blockage in the fuel cell stack 12 may cause cell voltage drop and / or voltage instability in the fuel cell stack 12. Liquid water can also be removed by the separation device 36 to prevent blockage or partial blockage in the ejector 24. Liquid water droplets in the branching portion of the concentration / branching nozzle 28 can create a virtual secondary venturi in the nozzle 28 and cause pumping instability to the ejector 24.

  The cathode side 16 of the stack 12 receives oxygen, for example, as a component in the air source 42. In one embodiment, the compressor 44 is driven by a motor 46 to pressurize the input oxygen. The pressurized air is then humidified by the humidifier 48 before entering the cathode side 16. Another separation device 50 (shown in phantom) may be located downstream of the humidifier 48. This separation device 50 can be used to remove liquid water from the humidified air stream before entering the cathode side 16 of the stack 12 at the input 52. Water droplets may exist downstream of the humidifier 48 by placing liquid water in the humidifier 48 at a high air flow rate. Liquid water can be removed by the separator 50 to prevent water blockage in the cells on the cathode side 16 that causes cell voltage drop and / or instability in the fuel cell stack 12. The output 54 on the cathode side 16 is coupled to a valve 56. A drain line 38 from the separator 36 and a drain line 58 from the separator 50 can be coupled to a line 60 downstream of the valve 56. In other embodiments, these drain lines may be connected to other locations within the fuel cell system 10.

  Other system configurations for the fuel cell system 10 can also be employed. For example, a turbine may be used in addition to the compressor 44 to cause a flow through the cathode side 16. In one example, a turbine is positioned downstream of the cathode stack outlet 54 and a separator is inserted between the cathode side 16 and the turbine to remove liquid water before fluid flow enters the turbine. .

  In order to create a flow through the anode side 14 and to cause a flow through the passive recirculation loop 34 in light of the use of the ejector 24, the ejector 24 typically has a significant pressure drop along the fuel cell stack 12. The pressure drop in the system must be overcome, including The illustrated system 10 does not include a pump or other device for causing flow in the recirculation loop 34. Thus, all compression work must be accomplished by the ejector, otherwise by what is referred to as a jet pump. In order to enable this function, the separating device 36 needs to have a small pressure drop along itself. Separation device 36 also needs to remove relatively large drops of water from the fluid to prevent water blockages in the recirculation flow caused by the drops in fuel cell stack 12 or ejector 24. Separator 36 allows vapor phase water and relatively small droplets to remain in the recirculation stream in flow path 40 and return to ejector 24 for humidification purposes. In one example, the separation device 36 removes water droplets having a diameter on the order of 1 mm or larger.

  In addition, when the separator 36 receives a fluid flow from the anode side 14, the separator 36 needs to be designed to use hydrogen gas. In general, hydrogen gas can cause material degradation or embrittlement problems. Therefore, the material used for the separation device 36 needs to be compatible with hydrogen. In addition, hydrogen is a small molecule and many conventional separation devices are not suitable for the use of hydrogen because conventional designs, for example, allow conventional screw-type bonds to leak. Other conventional separation devices may include rotating or moving parts that are incompatible with hydrogen, such as rotor blades. In this case, the lubricant can contaminate the fuel cell stack, or hydrogen can degrade or decompose the lubricant.

  Separator 50 also needs to remove relatively large drops of water from the fluid to prevent water blockage caused by drops in the flow at the cathode side 16 of the fuel cell stack 12. Separator 50 allows vapor phase water and relatively small droplets to remain in the humidification stream. According to one embodiment, the separation device 50 removes water droplets that are the same size or larger than the channel width of the flow field on the cathode side 16. In one example, the flow field flow path on the cathode side is 0.2 to 1.0 mm.

  2 and 3 show one embodiment of the separation device 100. The separation device 100 can be used as the separation device 36 or as the separation device 50 for the fuel cell system 10 shown in FIG. Separation device 100 has an upper portion 102 and a lower portion 104. These upper and lower portions 102, 104 define the interior separation chamber 106.

  The partition 108 divides the chamber 106 into an upper vortex chamber 110 and a lower collection chamber 112. The partition 108 can be a screen 116. In one embodiment, the divider 108 is secured in the lower portion 104 using spot welding or other processes. Screen 116 may have a relatively large mesh size and may be made of a material with a low contact angle to allow liquid to drip into collection chamber 112 while preventing liquid from spreading on screen 116. According to one embodiment, the contact angle of the screen 116 is less than 90 degrees. According to other embodiments, the contact angle of the screen 116 is less than 50 degrees.

  The lower portion 104 has a generally cylindrical side wall 118 and an end wall 120. Sidewall 118 and end wall 120 may be integrally formed as shown. In other embodiments, the sidewall 118 may taper to a frustoconical shape, a conical shape, or other suitable shape. The end wall 120 can be concave or bowl-shaped. In an alternative embodiment, the end wall 120 is planar.

  The collection chamber 112 can be large enough to collect a small amount of liquid water. The collection chamber 112 of the lower portion 104 may reduce in volume until the fluid that circulates in the vortex chamber 110 causes the liquid to bounce from the collection chamber 112 to the vortex chamber 110 through the screen 116. .

  The lower portion 104 has a suction pipe 122. The suction tube 122 is along the side wall 118 without fluid flowing through the suction tube 122 entering the chamber 106 and being forced to turn due to the geometry of the coupling between the suction tube 122 and the lower portion 104. It is joined in contact with the side wall 118 so as to flow smoothly. At an entry point 124 where fluid enters the chamber 110 from the suction tube 122, the fluid generally flows parallel to the sidewall 118.

  The lower portion 104 also has a drain tube 126. The drain tube 126 is located at the lowest point of the end wall 120 and is typically located at the center or center of the end wall 120 or along the longitudinal axis 136 of the separation device 100. By placing the drain tube 126 at the lowest point of the chamber 112, the liquid in the chamber 112 can be easily removed even when the vehicle or fuel cell is in a low ambient temperature environment where freezing may occur, for example. .

  The drain tube 126 may be sized so that liquid water does not block or cover the opening. The drain tube 126 may be made of a low contact angle material to prevent liquid from covering the opening.

  The upper portion 102 has an end wall 128 that supports the discharge pipe 130. The discharge tube 130 is coupled to the upper portion 102 so as to extend generally vertically from the end wall 128 to which it is connected. In other embodiments, the coupling angle between the discharge tube 130 and the end wall 128 may be variable. The discharge tube 130 has a portion of a tube 132 that extends as shown into the chamber 106 such that an inlet 134 from the chamber 106 to the discharge tube 130 is spaced from the partition 108.

  A tube 132 of the discharge tube 130 extends from the end wall 128 into the chamber 106. The tube 132 is combined with the side wall 118 of the lower portion 104 so as to form a flow path. The tube 132 has a cylindrical shape as a whole.

  According to one embodiment, the suction tube 122 is disposed proximate to the upper edge of the lower portion 104 so as to be proximate to the upper portion 102 of the separation device 100. The suction tube 122 is positioned higher than the end of the tube 132 so as to create and hold a vortex and prevent fluid flow from taking a shortcut through the chamber 106. The suction tube has a longitudinal axis 135.

  The discharge pipe 130 shares the longitudinal axis 136 with the separation device 100 so that the side wall 118 and the discharge pipe 130 are coaxial with each other. A drain tube 126 is also disposed along the longitudinal axis 136.

  In the illustrated embodiment, axis 135 is perpendicular to axis 136. In other embodiments, the arrangement of the shaft 135 relative to the separation device 100 and the shaft 136 can be changed, for example, so that flow is brought into the chamber generally against the sidewall 118 and also a downward component of the flow. is there. The axes 135 and 136 are isolated from each other so as not to intersect.

  In vehicle or fuel cell applications, the inlet and outlet tubes 122, 130 need not be arranged along a common axis, but may be in series with each other, as are many conventional separation devices. . This allows an improved mounting of the separation device 100 in the available space. The overall dimensions of the separation device 100 are illustrated in FIG. 2 according to one non-limiting example.

  According to one example, the ratio of the diameter 138 of the suction tube 122 to the diameter 140 of the chamber 106 is 1: 3. In other embodiments, the ratio of diameter 138 to diameter 140 can be between 1: 2 and 1: 8. The diameter of the chamber 106 is the diameter of the cylindrical side wall 118. The distance between the partition 108 and the inlet 134 to the discharge pipe 130 is equal to the diameter 142 of the discharge pipe 130. The inlet and outlet tubes 122, 130 may have equal diameters, but may have different diameters in alternative embodiments. In one embodiment, the suction tube 122 has a diameter of 25 mm and the discharge tube 130 has a diameter of 25 mm.

  The first portion 102 and the second portion 104 are coupled together using a clamping mechanism 146 or other known securing device suitable for handling hydrogen. The upper and lower portions 102, 104 have mating surfaces for sealing the chamber 106. The end wall 128 of the upper portion 102 can function as a mating surface for the upper portion 102. The lower portion 104 may have a flange 148 that extends from the sidewall 118 and functions as a mating surface for the lower portion 104. One of the upper and lower surfaces may have a groove 150 for an O-ring used to seal the chamber 106.

  Although the separation device 100 has been described as having an upper portion and a lower portion, the separation device may be configured in other ways in accordance with various embodiments of the present disclosure. For example, the two parts may be integrally formed and need not be disassembled. Both parts can be joined by welding or other methods.

  The operation of the separation device 100 will be described with reference to FIGS. The fluid flow from the anode 14 enters the separation device 100 through the suction pipe 122, and contains hydrogen gas, nitrogen gas, water vapor and liquid water. Fluid enters the chamber 110 either parallel to the sidewall 118 or tangentially. This reduces the overall pressure drop along the separation device. The side wall 118 of the chamber 110 and the extension part 132 act so as to guide the fluid in the chamber 110 to the flow path formed therebetween. In order to remove the liquid entrained in the fluid flow, the fluid is spun in the chamber 110 around the extension 132 as indicated by the arrows. Centrifugal acceleration generated by the rotating fluid flow causes the droplet to move toward the wall 118. The droplets impinge on the wall 118, and then by gravity, the liquid falls down the wall 118 and enters the collection chamber 112. The remaining fluid containing hydrogen gas, nitrogen gas, water vapor and relatively small water droplets continues to spin in the separation device 100. The relatively small water droplets continue to spin or rotate with the fluid flow because their mass is insufficient to move towards and collide with the wall 118 due to centrifugal forces.

  After entering the chamber 110 from the suction pipe 122, the fluid flows toward the discharge pipe 130 and thus turns 90 degrees. This 90 degree turn may be gradual while the fluid flow path forms a spiral or spiral pattern. The inlet 134 to the discharge pipe 130 is separated from the suction pipe 122 and deviated as a whole. The inlet 134 is also spaced from the wall 118 and is centrally located in the separation device 100 as a whole. To exit the chamber 110 towards the tube 132, the fluid is turned 180 degrees. This results in further separation of the water droplets carried in the fluid flow. Due to the geometry of the separation device 100, the fluid flow is turned 180 degrees and away from the wall to reach the inlet 134 of the discharge tube 130, as indicated by the arrows in FIG. Droplets that exceed a certain size are separated from the fluid flow because they cannot follow this turning due to their momentum. These droplets then travel to the collection chamber 112. The fluid flow has a continuous flow path between the suction pipe 122 and the discharge pipe 130 that is not disturbed as a whole. This reduces the pressure drop along the separation device 100.

  The momentum of the droplet and the force due to the centrifugal acceleration cause the droplet to continue straight toward the outer wall 118 of the separation device 100. The gas portion of the fluid flow has a fairly low concentration so that it can turn and flow along the curvature of the chamber 106. The initial diversion of the fluid flow after the inlet 124 causes a first stage of liquid water separation, where water impinging on the wall 118 flows down the wall 118 and into the lower collection chamber 112. As the fluid begins an annular or helical movement around the vertical axis 136 of the separation device 100, it diffuses into a relatively large volume within the chamber 110, reducing the flow rate. The fluid flow is diverted 90 degrees downward toward the inlet 134 of the discharge tube 130. The fluid flow then turns 180 degrees second due to the geometry of the separation device and enters the discharge tube 130 assuming that the diameter of the discharge tube 130 is approximately equal to the diameter of the suction tube 122. In some cases, it is forced to accelerate to a speed almost equal to the initial speed. Water droplets in the fluid stream are thrown downwards to the separation screen 116 and collection chamber 112 at an early stage of 180-degree turning. This is because water droplets cannot ride the flow because their momentum is too great, so the flow trajectory causes internal collisions with the separation device 100 and separation from the fluid flow. Only a low concentration of gas or very small droplets can take a fluid flow and make a second tight turn, flowing against discharge tube 130 against gravity. The water droplets that change the direction are dispersed so finely that they can be vaporized during mixing in the ejector 24.

  The screen 116 of the partition 108 creates a place for condensation to occur and also provides a flow smoothing effect for the fluid circulating in the vortex chamber 110. The screen 116 also acts to maintain a relatively quiet environment within the collection chamber 112 and prevents fluid movement such as splashing into the upper chamber 110. A collection chamber 112 under the screen 116 collects liquid water and directs it to the drain tube 126.

  During soaking of the fuel cell, for example, at or prior to starting the fuel cell, and during system operation, the separation device 100 can be used to remove water from the anode loop of the fuel cell. In addition, excess nitrogen can be removed from the anode side 14 of the fuel cell in a purification process. If the nitrogen concentration or partial pressure on the anode side 14 of the fuel cell is too high, the hydrogen concentration is insufficient, or the hydrogen partial pressure is too low, so the performance of the fuel cell 10 is degraded. By purging the anode side 14 of the fuel cell, excess nitrogen is expelled from the anode side 14 of the stack 12. A mixture of hydrogen, excess nitrogen, and liquid and gas phase water enters the separator 100 during the purification process. Separator 100 allows liquid water, excess nitrogen, and some hydrogen to exit from separator drain 126. Some hydrogen and other components in the stream may return to the ejector 24 through the separator discharge tube 130. The ejector 24 may also not work well when a high concentration of nitrogen is present because the concentration of nitrogen is higher than the concentration of hydrogen. Therefore, removing the excess nitrogen from the anode side 14 of the fuel cell during the purification process can improve overall fuel cell performance.

  FIG. 4 illustrates the pressure difference or pressure drop between a conventional industrial centrifuge and the separator of FIG. 2 at various mass flow rates. The unit of pressure drop is millibar (mbar). The unit of mass flow rate is kilogram / hour (kg / hr). The conventional separation device has an overall size approximately twice that of the separation device of FIG. A conventional separation device is of the conventional type having a series of suction and discharge tubes and a cylindrical chamber disposed generally below. Conventional separators sharply redirect the fluid flow both when entering and leaving the separator. The pressure drop along the conventional separator is shown by line 160. The pressure drop along the separation device of FIG. As can be seen from FIG. 4, the pressure drop along the separation device according to the present disclosure is significantly lower than the prior art at all tested flow rates. In the fuel cell system 10, the typical continuous mass flow rate in the recirculation loop during normal operation is about 20 kg / hr. A typical recirculation loop mass flow rate for a fill operation during a cold start of the fuel cell system 10 is about 45 kg / hr. Of course, these values are only typical examples of fuel cell systems and are used as non-limiting examples.

  Various embodiments of the present disclosure relate to non-limiting advantages. For example, realizing a small pressure drop in the separator allows the use of a passive recirculation loop on the anode side of the fuel cell. A small pressure drop occurs in the separator due to smooth tangential fluid flow into the separator and by not using additional mesh members in the gas phase fluid flow path within the separator. The separation device is designed to remove relatively large drops of water from the fluid stream while leaving water vapor and relatively small sized drops. Thus, the separation device does not have very high efficiency for total water removal. This is acceptable for fuel cell applications because humidity is required on both the anode and cathode sides for the fuel cell to function properly. Since the flow at the anode is mixed with a fresh fresh hydrogen supply prior to entry into the stack, small droplets can be vaporized prior to reaching the stack. In addition, the stack module can tolerate the intake of a certain amount of liquid water without reducing cell voltage stability. This amount is usually in the range of 5-30 cc / min. The design of the separation device provides a small, dense and easy to manufacture device that allows its use in applications such as fuel cell systems in vehicles where mounting, weight and cost are current concerns. In addition, the structure and assembly of the separation device is designed to be compatible with hydrogen molecules in the fluid flow, such as downstream on the anode side.

  Although exemplary embodiments have been described above, these embodiments are not intended to describe all possible forms of the invention. It is to be understood that the terms used in the specification are words of description rather than limitation, and various modifications can be made without departing from the spirit and scope of the present invention. In addition, the features in the various embodiments can be combined to form other embodiments of the invention.

Claims (20)

A fuel cell system comprising a fuel cell stack and a separation device in fluid communication with the fuel cell stack,
The separation device includes:
First and second ends joined by sidewalls to form a chamber;
A suction pipe coupled in contact with the side wall;
A discharge pipe coupled to the first end and extending to the chamber to form a flow path between the side wall;
A fuel cell system having a liquid drain tube coupled to the second end. The fuel cell system according to claim 1, wherein
The separator is a fuel cell system having a partition extending from the side wall through the chamber and positioned between the discharge pipe and the second end. The fuel cell system according to claim 1, wherein
The fuel cell stack has an anode side and a cathode side,
The fuel cell system further comprises a recirculation loop in fluid communication with the anode side,
The recirculation loop includes the separation device, and the separation device is downstream of the anode side. The fuel cell system according to claim 3, wherein
A fuel cell system further comprising an ejector in fluid communication with the anode side and upstream of the anode side. The fuel cell system according to claim 4, wherein
The fuel cell system, wherein the ejector is in fluid communication with the recirculation loop, and the ejector is downstream of the separator. The fuel cell system according to claim 1, wherein
The fuel cell stack has an anode side and a cathode side,
The fuel cell system further comprises a humidifier in fluid communication with the cathode side and upstream of the cathode side,
The separation device is a fuel cell system inserted between the humidifier and the cathode side. A liquid separator for a fuel cell system, comprising:
First and second ends joined by sidewalls to form a chamber;
A suction pipe coupled in contact with the side wall;
A discharge pipe coupled to the first end and extending to the chamber to form a flow path between the side wall;
A separator comprising a liquid drain tube coupled to the second end; The separation device of claim 7,
A separation device further comprising a screen positioned between the inlet to the discharge pipe and the second end. The separation device of claim 8,
Separation device wherein the inlet to the discharge tube is separated from the screen by approximately the diameter of the discharge tube. The separation device of claim 7,
The separation apparatus has a generally cylindrical extension that extends into the chamber such that an inlet to the discharge pipe is spaced from the first end. The separation device of claim 7,
The suction pipe is a separation device located between the first end and a region of the side wall close to the inlet of the discharge pipe so that inflow fluid enters the flow path of the chamber. The separation device of claim 7,
The separation apparatus, wherein the discharge pipe is coupled vertically to the first end as a whole. The separation device of claim 7,
Separation device in which the longitudinal axis of the suction pipe is generally perpendicular to the longitudinal axis of the discharge pipe. The separation device of claim 7,
The separation device, wherein the discharge pipe is coaxial with the side wall. The separation device of claim 7,
The first end portion has a planar shape as a whole, and the second end portion has a concave shape. The separation device of claim 7,
The separation device, wherein the side wall is generally cylindrical. The separation device of claim 7,
The separation device wherein the ratio of the diameter of the suction pipe and the discharge pipe to the diameter of the chamber ranges from 1: 2 to 1: 8. A fuel cell system comprising a fuel cell stack and a separation device in fluid communication with the fuel cell stack,
The separation device has a first part and a second part forming a chamber;
The first portion has a continuous inner wall and an end wall;
A suction pipe is coupled to the inner wall, and a liquid drain pipe is coupled to the end wall;
The fuel cell system, wherein the second part includes an end wall and a discharge pipe extending to the chamber so as to form a flow path between the inner wall of the first part. The fuel cell system of claim 18, wherein
The suction pipe is coupled in contact with the inner wall of the first portion;
The fuel cell system, wherein the discharge pipe is coupled vertically to the end wall of the second portion as a whole. The fuel cell system of claim 18, wherein
The first portion has a flange extending from the inner wall to the end wall;
The fuel cell system, wherein the flange closes the chamber together with the end wall of the second portion.