JP2001355588A - Power recovery scroll fluid machine and fuel cell system using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a fuel cell system having a large-capacity compressor capable of being operated by the small capacity of an electric motor. SOLUTION: This fuel cell system is provided with a both tooth-type scroll fluid machine 60 in which a compressor 59 and an expander 64 are integrated with each other. This scroll fluid machine is rotationally driven by an electric motor 69. Air compressed by the compressor reacts with hydrogen gas in a fuel battery main body 50, its moisture is removed by a water collector 63, the air is guided to the expander, and a part of power of the compressor is recovered. The water collected by the water collector is guided to the compressor and used for cooling or lubrication.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll fluid machine and a fuel cell system using the same, and more particularly, to a power recovery scroll fluid machine suitable for a fuel cell vehicle and the like and a fuel cell system using the same.

[0002]

2. Description of the Related Art In a scroll fluid machine, examples in which scroll wraps are provided on both sides of a mirror plate and both sides of the mirror plate are used as working chambers are disclosed in JP-A-8-128395 and JP-A-7-14599. This is disclosed in, for example, Japanese Unexamined Patent Publication No. 8-61264. In the publications described in these publications, the wraps have the same spiral direction in order to operate as a compressor. Note that Japanese Patent Application Laid-Open Nos. 7-14599 and 8-6
In the scroll compressor described in Japanese Patent No. 1264, the phase of the spiral is changed between the front and back of the end plate, thereby reducing the discharge pulsation of the fluid.

[0003] Recently, fuel cells have attracted attention as applications of positive displacement air compressors. A fuel cell utilizes electric power generated when hydrogen and oxygen are combined. Hydrogen used in this fuel cell uses hydrogen gas or alcohol stored as alcohol, and oxygen uses atmospheric oxygen. Even if oxygen in the air is chemically reacted with hydrogen as it is, the energy efficiency is not good. Therefore, in order to effectively use oxygen in the air for a fuel cell, the air is compressed as described in JP-A-7-14599. are doing.

Some types of fuel cells, for example, a polymer electrolyte fuel cell (PEFC), are provided with an electrolyte membrane for ion exchange. In order to operate the electrolyte membrane stably for a long period of time. It is necessary to wet the electrolyte membrane with water, and water supply is essential for this type of fuel cell.

[0005]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 8-128 is disclosed.
395, JP-A-7-14599 and JP-A-8
All of the scroll fluid machines described in JP-A-61264 are not intended to be used for fuel cells and the like, and therefore operate as compressors. Therefore, when the orbiting scroll is orbited in one direction, the closed spaces formed on both sides of the end plate function as compression working chambers. Therefore, one of the front and back sides of the end plate of the orbiting scroll is a compressor,
No consideration was given to using the other as an expander.

On the other hand, in the fuel cell device described in Japanese Patent Application Laid-Open No. 7-14599, an attempt is made to recover power by providing a generator on a common shaft of a compressor and an expander. And it is suitable for a fuel cell device having an electrolyte membrane. But,
In order to mount a fuel cell on a vehicle, further downsizing and energy saving are desired.

The present invention has been made in view of the above-mentioned disadvantages of the related art, and has as its object to enable operation of a large-capacity compressor with a small motor capacity. Another object of the present invention is to reduce the required power of an air compressor used in a fuel cell system and improve the energy efficiency of the entire fuel cell system. The present invention aims to achieve at least one of these objects.

[0008]

A first feature of the present invention to achieve the above object is to provide a orbiting scroll having a head plate and spiral wraps formed on both sides of the head plate, and a wrap of the orbiting scroll. A pair of fixed scrolls having meshing wraps are provided, and the spiral directions of the wraps formed in the orbiting scroll are opposite to each other.

Preferably, a discharge port for compressed air compressed by the power recovery type fluid machine is formed at one central portion of the pair of fixed scrolls, and the other fixed scroll is provided with the power recovery type fluid machine. A suction port for supplying gas at a pressure higher than the atmospheric pressure is formed. More preferably, a plurality of crankshafts for orbiting the orbiting scroll are provided, or the crankshaft is held substantially at the center of the orbiting scroll, and cooling fans are attached to both ends of the crankshaft.

[0010] It is also possible to form a means for injecting water into the working chamber formed by the wrap of the fixed scroll on the side where the discharge port is formed in the center and the wrap of the orbiting scroll meshing with the wrap. Good.

A second feature of the present invention to achieve the above object is that an electric motor, a scroll fluid machine driven by the electric motor, and an electric power generated by reacting air compressed by the scroll fluid machine with hydrogen gas. A fuel cell body for extracting
A flow path for guiding the air sent from the fuel cell body to the scroll fluid machine, wherein the scroll fluid machine uses one of the double-toothed scroll fluid machines as a compressor and the other as an expander.

[0012] Preferably, a collector for collecting moisture is interposed in a flow path for guiding air sent from the fuel cell body to the scroll fluid machine.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of a system including a power recovery type scroll fluid machine according to the present invention, which is an example of a compressed air supply type fuel cell system. FIG. 1 shows in detail a system for supplying compressed air to the fuel cell body and a water circulation system in the fuel cell system.
The illustration of the reformer, its peripheral devices, the devices related to the conversion and control of the generated power to AC, and the wiring and piping are omitted.

In the fuel cell body 50, the electrolyte membrane 51 is sandwiched between a hydrogen electrode (anode) 52 and an oxygen electrode (cathode) 53, and DC power is extracted from these two electrodes by a power line 54. Although the material of the electrolyte 51 varies depending on the type of the fuel cell, the present embodiment uses a polymer electrolyte membrane. The surface of the hydrogen electrode 52 faces a hydrogen chamber 55 to which a gas containing a large amount of hydrogen as a fuel is supplied. Similarly, the surface of the oxygen electrode 53 faces the air chamber 56. The hydrogen chamber 55 is supplied with stored hydrogen or hydrogen extracted from a compound containing hydrogen using a reformer.

The air in the atmosphere is compressed and sent to the air chamber 56 through the following channel system. In this system, the air is sucked from an air filter 57 that prevents dust floating in the air from entering, and is drawn into a suction port on a compressor side 59 of a power recovery type scroll fluid machine 60 via a suction channel 58. Leading. Then, the air compressed by the power recovery type scroll fluid machine 60 is guided from the discharge port of the scroll fluid machine 60 to the air chamber 56 via the upstream flow path 61 which is a pressure-resistant pipe.

The details of the power recovery type scroll fluid machine 60 will be described later. The downstream pipe 62 connected to the outlet of the air chamber 56 is also a pressure-resistant pipe, and a water collector 63 is provided in the middle of the downstream pipe 62. The compressed air passing through the water collector 63 is used as a power recovery type. It is guided to the expander side 64 of the scroll fluid machine 60. The air expanded by the expander 64 is discharged to the atmosphere via the silencer 65.

In the water collector 63, the gas is once cooled to a temperature below the dew point, and the liquefied and precipitated water is separated by gravity. A water storage tank 66 is formed below the water collector 63. A water pipe 67 is connected to the bottom of the water storage tank 66, and the water pipe 67 is connected to a power recovery type scroll fluid machine 60 via an electric valve 68. The water pipe 67 communicates with a compression working chamber formed inside the scroll fluid machine 60.

The performance and reliability of the scroll fluid machine 60 fluctuate greatly depending on where in the compression working chamber the water flowing in the water pipe is guided. That is, if the injection position is too close to the discharge side or downstream from the discharge port, the injection of water does not help cooling during the compression of the working air, and the compression power is not significantly reduced. Further, since the internal pressure at the injection position is high, it becomes difficult to inhale the differential pressure.

On the other hand, if the injection position is provided upstream of the suction port, air cannot be sucked in by the amount of water vaporized, and the volume efficiency is reduced. Further, since the wall surface of the flow path is wet, freezing and corrosion may occur when the scroll fluid machine 60 is stopped. Considering these, it is desirable to provide a water inlet at the next position. The orbiting scroll of the scroll fluid machine 60 orbits, and the compression working chamber formed by the fixed scroll and the orbiting scroll has the maximum volume, closing the suction port. On the fixed scroll side,
A water inlet is formed at this position or at a swirling position slightly before this position.

When operating using a scroll fluid machine 60 in which a compressor and an expander are integrated, under normal conditions,
It is impossible to drive the compressor 59 with the output of the expander 64 due to insufficient power. Therefore, the output shaft of the electric motor 69 is connected to the scroll fluid machine 60 via a belt or directly.
It is connected to.

A temperature sensor 70 is mounted inside the upstream channel 61. A temperature sensor 71 is also attached to the surface of the oxygen electrode 53. These temperature sensors 70,
The output of 71 is input to the control device 72. The control device 72 outputs a control signal 73 for the motor-operated valve 68.

A heating wire heater 7 is provided at the bottom of the water storage tank 66.
5 are arranged. Further, a temperature sensor 74 is provided in the water storage section.
Is installed. The outer periphery of the water storage tank 66 is covered with a heat insulating material 76. The heater 75 is supplied with electric power from a storage battery 78 via a control panel 77. The power line 54 of the fuel cell main body 50 is also connected to the control panel 77. A voltage converter (not shown) is interposed in the middle of the power line 54 as necessary. The control device 72 instructs the energization / stop of each power line from the control panel 77.

The operation of the fuel cell system thus configured will be described below. First, the operation at the time of steady operation will be described. The dust is removed from the air by an air filter 57, and the air is sucked into an air compressor 59 through a suction passage 58. Air begins to be sucked into the compression working chamber from the suction port during the expansion of the compression working chamber. When the volume of the compression working chamber is almost maximum, the suction port is closed and the suction of air is completed, and then the volume of the compression working chamber is gradually reduced and the sucked air is compressed. Around the start of the compression, water is injected into the compression working chamber. Since the temperature of the water is about the same as or slightly higher than the ambient temperature, it is possible to cool the intake air that has been compressed and has a higher temperature.

Since water has a very high specific heat per volume as compared with air, and latent heat of vaporization can be used at high temperatures, the temperature of compressed air injected with water is much lower than that of dry compressed air. . Because the compressed air was cooled with water,
This compression process approaches the isothermal compression change from the adiabatic compression change. Since the compression power is reduced as the change approaches the isothermal compression change, the compression efficiency is also improved in this embodiment. When the rotation of the scroll advances and the compression working chamber reaches a predetermined position, the discharge port is opened to discharge the compressed air from the scroll fluid machine 60.

Incidentally, compressed air leaks from a small gap formed between the scroll wraps, which lowers the efficiency of the compressor. However, when water is injected into the compressor side 59, the water closes the gap, so that leakage can be reduced.

As described above, it is necessary to wet the electrolyte membrane 51 with water. Therefore, if the dried high-temperature air flows into the air chamber 56, it is dried together with the oxygen electrode 53, and the efficiency of the electrolyte membrane 51 is reduced. In the present embodiment, since the supply air contains a large amount of water vapor, it is possible to reduce the amount of water permeating the oxygen electrode 53 and dissipating from the electrolyte, thereby preventing the electrolyte membrane from running out of water. Further, depending on the temperature conditions, moisture can be supplied by dew condensation on the surface of the oxygen electrode 53.

At the oxygen electrode 53, hydrogen ions transmitted through the electrolyte membrane 51 from the hydrogen electrode 52 and electrons transmitted through the power line 54 combine with oxygen in the compressed air to form water.
Part of the water becomes steam and enters the air chamber 56. Therefore, the air discharged from the fuel cell main body 50 contains a large amount of water vapor.

In the water collector 63, steam is liquefied and separated from the discharged compressed air. The pressure of the compressed air from which the moisture has been removed drops in the expander 64. At the time of this pressure drop, rotational power for rotating the expander 64 is generated. Expander 64
Is released from the silencer 65 to the atmosphere. In addition, with only the power generated by the expander 64,
Since it is not enough to rotate the compressor 59, the electric motor 6
9 supplements the driving force of the compressor.

The water dropped in the water storage tank 66 below the water collector 63 is guided to the compressor 59 via the water pipe 67, and is again injected into the intake air. Water collector 3 including water storage tank 66
Is higher than the pressure in the compression working chamber at the compression start position at which the pressure becomes substantially atmospheric pressure. Therefore, it is possible to send water to the compression working chamber by utilizing the pressure difference between the water storage tank 66 and the pressure in the compression working chamber, and a pump is not required. In this embodiment,
Although the water injection position is the compression working chamber, it may be injected into the suction passage 58.

The power generation capacity of the fuel cell main body 50 also changes depending on the electrolyte membrane 51 and the ambient temperature of the electrolyte membrane 51. It is desirable that the temperature at these locations be higher than the air temperature.
During normal operation, it is necessary to balance the heat generated by the fuel cell itself, the temperature of the supplied air and fuel, and the heat radiation from each device constituting the fuel cell. The temperature control of each part of the fuel cell system will be described below.

The temperature of the oxygen electrode 53 is detected by the temperature sensor 71 and is set as the temperature of the fuel cell main body 50. The temperature of the supplied air is detected by a temperature sensor 70. Based on these two pieces of temperature information, the control device 72 calculates the optimal opening degree of the motor-operated valve 68 and outputs it to the motor-operated valve 68 as a control signal 73. For example, if the temperature is too high, the flow path loss is reduced to increase the flow rate of water, and an attempt is made to cool with more water. Conversely, if the temperature is too low, reduce the amount of water.

The operation at the time of starting the fuel cell system will be described below. At start-up, the temperature is close to the ambient temperature in any place of the fuel cell system. Therefore, the power generation capacity is low in this state. Depending on the use of the fuel cell, a quick start-up, that is, a short warm-up operation time is required, so the operation is performed as follows.

The controller 72 instructs the water injection amount to be reduced or the water injection to be stopped until a set time has elapsed since the start-up or until a predetermined temperature is reached after the start-up. Since the amount of water injected is reduced, the change in the compressor 59 approaches an adiabatic change, and the discharge air temperature rises. When the increased compressed air is supplied to the air chamber 56, the fuel cell main body 50 is warmed, so that the temperature of the entire fuel cell system quickly approaches the optimum value.

In this warm-up operation, the compression process shifts from the isothermal change and approaches the isothermal change, so that the power of the compressor 59 increases. However, since the warm-up operation time is shorter than the normal operation time, the influence on the energy consumption is small. Further, since the injection of water is reduced, the air containing less water vapor is supplied to the electrolyte membrane 51, so that the water is dissipated from the electrolyte membrane. However, since the warm-up operation is performed for a short time, the influence on the electrolyte membrane is small. In addition, in order to completely prevent the drainage of the electrolyte membrane, water may be directly supplied by industrial water or a pump provided in the factory equipment.

When the fuel cell system is used under cold conditions, a dry operation is performed before stopping in order to prevent freezing. In the drying operation, the injection of water is stopped as in the start-up operation. Then, the operation is stopped after the moisture inside the compressor 59 and the air passages 58 and 62 is reduced. After the compressor 59 is stopped, the electric valve 68 is opened, and the water remaining in the water pipe 67 is opened.
It returns to the water storage tank 66 using gravity. Since the water is concentrated in the water storage tank 66, freezing can be easily prevented by using a heater or the like as described below.

Even when the fuel cell body, the compressor, and the expander are stopped, the control device 7 keeps operating. At the same time, the temperature of the water in the water storage tank 66 is continuously monitored by the temperature sensor 74. When the temperature of the water gradually decreases and falls below a predetermined temperature (for example, 5 ° C.), a command is issued to the switchboard 77 and the battery 7
8 is supplied to the heater 75 to heat the water. this,
Continue until a rise in water temperature (for example, 7 ° C. or more) is confirmed.
Thereby, freezing of the water in the water storage tank 66 can be prevented.

When the anti-freezing function operates for a long period of time, a shortage of power in the storage battery 78 occurs. Therefore, the controller 72 monitors the consumption of the storage battery 78, and when it is determined that the storage battery 78 has been consumed, the fuel cell system is automatically started. Then, the electric power generated in the fuel cell main body is transmitted to the storage battery 78 using the power line 54. When the control device determines that the storage battery is sufficiently charged, the fuel cell body, the compressor, and the expander are stopped, and the operation is returned to the antifreeze operation again.

Next, the details of the power recovery type scroll fluid machine used in the fuel cell system will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 2 is a longitudinal sectional view of the overall structure of the power recovery type scroll fluid machine. FIG. 3 is a diagram for explaining the spiral direction of the wrap of the orbiting scroll, and is a cross-sectional view, a top view, and a bottom view of the orbiting scroll. FIG.
FIG. 3 is a cross-sectional view taken along the line AA of FIG. 2, and is a diagram illustrating a meshing state of wraps. For convenience of explanation, FIG.
Crankshafts 4, 5 and balance weight 17,
18, the bearing 11 disposed on the orbiting scroll 3 is not shown. In addition, since the sectional view taken along the line BB of FIG. 2 is almost the same as that of FIG. 4, it is omitted.

FIG. 5 is a side view of the power recovery type scroll fluid machine of FIG. The opposite side view has a structure in which the timing belt 11 and the toothed pulley 25 are added to FIG. FIG. 6 is a bird's-eye view of the power recovery type scroll fluid machine, and shows the orbiting scroll 3 taken out of the fixed scroll for convenience of explanation.

As shown in FIG. 2, the power recovery type scroll fluid machine 100 includes a pair of fixed scrolls,
And the orbiting scroll 3 sandwiched between the fixed scrolls. A spiral scroll wrap 1 b is formed on the orbiting scroll 3 side of the fixed scroll 1, and a spiral scroll wrap 2 b is similarly formed on the orbiting scroll side 3 of the fixed scroll 2. The orbiting scroll 3 has a head plate 3a and scroll wraps 3b and 3c formed on both sides of the head plate 3a in a spiral shape.

Scroll wrap 1b of fixed scroll 1
Is engaged with the scroll wrap 3a of the orbiting scroll 3, and the scroll wrap 2b of the fixed scroll 2 is engaged with the scroll wrap 3c of the orbiting scroll 3. The wraps 3b and 3c of the orbiting scroll 3 have a predetermined thickness, and the envelope when the orbiting scroll 3 orbits with a constant radius is the basic line of the fixed scroll wrap.

As shown in FIG. 3, the spiral directions of the scroll wraps 3b and 3c of the orbiting scroll 3 are opposite to each other. These scroll wraps 3b, 3c
Is an involute curve. The orbiting scroll 3 and the fixed scrolls 1 and 2 mesh with each other in a non-contact state with a substantially small gap. End plate 3 of orbiting scroll 3
A compression working chamber 14 is formed on one side of a, and an expansion working chamber 15 is formed on the opposite side. These working chambers 14, 15
Have almost the same shape, only the compression working chamber 14 is illustrated in FIG. The compression working chamber 14 forms a crescent-shaped room by the fixed scroll wrap 1b and the orbiting scroll wrap 2b. In the scroll fluid machine, another compression chamber 14b is formed axially symmetrically with respect to the central axis. The volume of the working chamber 14b is
It is almost the same as the working chamber 14.

As the orbiting scroll 3 orbits, the compression working chamber 14 moves continuously to the center. Then, as the compression working chamber 14 moves from the outer peripheral portion toward the center, the volume of the compression working chamber 14 decreases. Expansion working chamber 1
In the case of 5, in FIG. 4, the crescent-shaped working chamber 15 (corresponding to the reference numeral 14 in the figure) continuously moves from the center to the outer periphery with the turning movement of the turning scroll 3. And, as the expansion working chamber 15 moves from the center to the outer periphery,
The volume of the expansion working chamber 15 increases.

At the center of each of the pair of fixed scrolls 1 and 2, there is provided a communication passage for guiding the air in the working chamber having a reduced volume to the outside of the scroll fluid machine. The fixed scroll 1 has a high pressure gas discharge port 4 communicating with the compression working chamber, and the fixed scroll 2 has a high pressure gas suction port 5 communicating with the expansion working chamber.

Since the compressor side and the expander side of the scroll fluid machine 100 have almost the same configuration, the compressor side will be described below unless otherwise specified. A groove is formed at the tip of each of the wraps 1b, 2b, 3b, 3c of the fixed scrolls 1, 2 and the orbiting scroll 3 along the spiral of the wrap. In this groove, 4
A chip seal formed of a composite resin material containing a fluorinated ethylene resin or a polyimide resin as a main component is fitted.

A plurality of chip seals are arranged in the direction in which the groove extends. By arranging a plurality of tip seals, the formability and assemblability of the tip seal and the thermal expansion when the scroll fluid machine is operated can be more easily absorbed than when a single tip seal is used. As a result, the sealing performance and the reliability of the tip seal can be improved.

FIG. 4 shows the flow of air in the scroll fluid machine 100. A plurality of ports 2 communicating with the scroll portion on the outer diameter side of the scroll portion of the fixed scroll 1
2, 23 are provided. This port is a discharge port on the compressor side and an exhaust port on the expander side.
The suction ports 22 and 23 are open on the side surface of the fixed scroll 1. A flange is formed at the opening of each of the suction ports 22 and 23, and a suction pipe (not shown) is connected to the flange.

Returning to FIG. 3, the suction gas flowing from each suction port 22, 23 is separated from the outside air and
It flows into 21. A dust trap 1c is provided on the outer peripheral portion of the scroll wrap 1b of the fixed scroll 1 so that outside air does not enter the suction chambers 20 and 21. The dust lap 1c is annular. As in the case of each of the scroll wraps 1b, 2b, 3b, and 3c, a groove is formed at the distal end, and a dust seal is fitted into the groove. The same applies to the fixed scroll 2.

On the left and right sides of the orbiting scroll 3 with the wrap portions 3b and 3c interposed therebetween, holes for mounting the crankshaft 7 and the auxiliary crankshaft 8 having eccentric portions are formed.
Here, the eccentric amounts of the crankshaft 7 and the auxiliary crankshaft 8 are the same. The two crankshafts 7, 8 are held by the orbiting scroll 3 via bearings 9a, 9b attached to eccentric portions.

When the scroll fluid machine operates, thermal expansion occurs inside the scroll fluid machine due to the heat of compression of air. Since this thermal expansion is not uniform, thermal distortion due to the difference in thermal expansion occurs. In order to solve this problem, a thermal expansion difference absorbing mechanism 10 is provided on the outer peripheral side of the bearing 9b of the auxiliary crankshaft 8.
Is provided. The thermal expansion difference absorbing mechanism member 10 is made of an annular resin, rubber, engineering plastic, metal spring, or the like.

In order to rotate the two crankshafts 7 and 8 synchronously, a synchronous driving means such as a timing belt 11 is provided on the side surface of the fixed scroll 2 (see FIG. 5). By rotating the crankshafts 7 and 8 synchronously, the orbiting scroll 3 performs an eccentric orbiting motion while its rotation is prevented.

The air compressed in the compression working chamber gathers at a substantially central portion of the scroll fluid machine, and is led out of the scroll fluid machine from a discharge port 4 formed in the fixed scroll 1. Radiation fins 1d are provided on the outer surface around the discharge port 4.
Is provided. In order to promote heat exchange with the radiation fins 1d, the ends of the fins 1d are covered with covers to form cooling air flow paths. On the other hand, fixed scroll 2
A suction port 5 for sucking high-pressure air is provided at a central portion on the side.

As shown in FIG. 6, on the upper surface side of the fixed scroll 2, a plurality of cooling air intakes 2e are formed. A substantially similar cooling air discharge port 2f is also formed on the lower surface side of the fixed scroll 2. As shown in FIG. 4, a part of the cooling air sucked from the upper intake 2e is discharged to the discharge port 2f through a plurality of head cooling holes 12 formed in the head of the orbiting scroll 3, and the rest of the cooling air remains. It is guided to the discharge port 2f through a space 6 formed by the two fixed scrolls 1 and 2.

The wrap portion 3b of the orbiting scroll 3
The cooling air that has flowed in the vicinity of 3c
c, it is prevented from flowing into the interior, and the space 6
Flows into. At this time, the periphery of the crankshaft 7, bearings, the outer peripheral portion of the orbiting scroll 3, the inner wall surfaces of the fixed scrolls 1 and 2, and the dust traps 1c and 2c of the fixed scroll are cooled.

A flange portion 16 is provided on the outer periphery of the fixed scrolls 1 and 2, and both fixed scrolls 1 and 2 are bolted together by the flange portions. At the time of fastening, the relative positions of the fixed scrolls in the X-Y direction and the rotation direction are adjusted using the positioning means 13.

As described above, the crankshaft 7 is held by the orbiting scroll 3.
2 is also held via a rolling bearing 17a and a bearing 18a. The crankshaft 7 is also provided with a balance weight portion 19a for canceling imbalance caused by the orbiting movement of the orbiting scroll 3. The auxiliary crankshaft 8 is the same as the crankshaft 7, and the fixed scrolls 2, 1
Are held via rolling bearings 17b and bearings 18b, and a balance weight portion 19b is also formed.

A pulley 24 is attached to the crankshaft 7 via key means for preventing relative slippage. The power of an electric motor (not shown) is supplied to the pulley 24.
Further, the crankshaft 7 and the auxiliary crankshaft 8 are synchronously rotated by the timing belt 11 interposed between the toothed pulleys 25a and 25b attached to the shaft ends.

The fixed scrolls 1 and 2 and the orbiting scroll 3 are preferably made of a light material having good heat conductivity, such as an aluminum alloy. Also, in order to prevent seizure even if the laps or the lap and the end plate surface are in contact with each other or to lubricate, the inner surface of the scroll fluid machine has a surface such as anodized film treatment or resin coating compatible with aluminum alloy. It is desirable to apply a treatment.

The operation of the scroll fluid machine configured as described above will be described first on the compressor side. When power is transmitted to the pulley 24 by the belt, the crankshaft 7 rotates. At the same time, the auxiliary crankshaft 8 connected by the timing belt 11 rotates synchronously. The orbiting scroll 3 locked to the two crankshafts 7 and 8 makes an orbital motion eccentric by the amount of eccentricity of the crankshaft without rotating.

When the orbiting scroll 3 orbits, air flows into the suction chambers 20 and 21 from the suction ports 22 and 23. The inflowing air is compressed to a predetermined pressure by reducing the volume by moving the compression working chamber 14 formed by the orbiting scroll 3 and the fixed scroll 1 from the outer peripheral portion to the central portion. The compressed high-pressure air is supplied from the discharge port 4 formed in the fixed scroll 1 to the outside of the scroll fluid machine.

It should be noted that the compression working chamber 14 is
May be provided at a position before reaching the pressure, that is, at the upstream side of the compression working chamber 14, for mixing water into the suction gas. At the time of water injection, pumping or pressure difference by a pump is used. The position for injecting water is not limited to the suction ports 22 and 23, but may be the suction chambers 20 and 21 or the compression working chambers 14.
It may be. When water is injected into the compression working chamber 14 in this manner, heat generation due to compression can be suppressed to a low level. In addition, when water is interposed in the seal portion between the scroll wraps, the sealing effect is enhanced, and when the seal portion comes into contact, water serves as a lubricant, so that occurrence of abnormal wear can be suppressed.

Next, the operation of the expander will be described.
When gas (air) having a pressure higher than the atmospheric pressure is introduced into the suction port 5 of the fixed scroll 2, the orbiting scroll 3 orbits in a direction different from the compressor side due to a pressure difference between the inside and outside of the expansion working chamber 15. I do. As a result, the two crankshafts 7,
8 rotates without power from pulleys 25a and 25b.

The high-pressure air in the expansion working chamber 15 gradually moves to the outer peripheral side while orbiting the orbiting scroll 3.
At that time, the pressure of the high-pressure air also gradually decreases. When the high-pressure air expands, the temperature of the air decreases, so that there is also an effect of cooling the scroll member. That is, the heat generated in the compression working chamber can be cooled by the cold heat in the expansion working chamber. Note that water may be injected into the expander. Injecting water into the expander allows the entire scroll fluid machine to be kept at a low temperature.

In the orbiting scroll 3, since the winding directions of the spirals are opposite to each other on the front and back of the end plate, the compression working chamber side of the orbiting scroll performs a compression operation, and the opposite expansion working chamber expands. Therefore, the power required for the compression operation is reduced by the output of the expander. As a result, the power supplied to the crankshaft 7 can be significantly reduced.

During operation of the scroll fluid machine, the gas pressures in the working chambers 14 and 15 on the front and back of the orbiting head plate 3 are balanced, so that the sum of the thrust gas forces in the working chambers 14 and 15 is substantially equal. Since the thrust forces are balanced, the orbiting scroll 3 is not strongly pressed against any of the fixed scrolls 1 and 2. Therefore, the load acting on the tip seal provided on the tip end surface of the wrap can be reduced, and the wear of the tip seal can be reduced. Further, since a large thrust force does not act on each of the bearings 17, 18 supporting the crankshafts 7, 8, the life of the bearings can be extended.

In this embodiment, the fixed scroll 1
A fin is provided on the outer surface side of 2 to form a cooling passage, a cooling passage is formed in the end plate of the orbiting scroll 3, and a cooling passage is also formed between the outer periphery of the fixed scroll and the outer periphery of the orbiting scroll. The outside can be cooled all at once. Thereby, the thermal expansion of both the fixed scroll and the orbiting scroll can be reduced, the amount of thermal expansion can be easily managed, and the maintenance and management of the gap between the scroll wraps can be easily performed. If the gap between the scroll wraps is kept constant, the reliability and performance of the scroll are improved.

FIG. 7 shows another embodiment of the present invention. The present invention is different from the above-described embodiment in that the crankshaft 30 is made into one, and the fan 38a,
8b, and one end of the shaft is connected to the output shaft of the electric motor 37 via the coupling 36. The crankshaft 30 is disposed at the center of each of the fixed scrolls 31 and 32 and a double-toothed orbiting scroll 33 having a scroll wrap that meshes with each of the fixed scrolls 31 and 32. Further, since the crankshaft 30 is provided at the center of the orbiting scroll 33 and the fixed scrolls 31 and 32 supported by bearings 34 and 35, the compression working chamber 3 is provided.
The discharge air discharged from 9 is guided from a discharge port formed near the center of the fixed scroll 31 to a discharge port 41 formed on a side surface of the fixed scroll. Similarly, high-pressure air is guided from the suction port 42 formed on the side surface of the fixed scroll 32 to the expansion working chamber 40 through the suction port formed near the center of the fixed scroll 32. Orbiting scroll 3
On the outer peripheral portion of 3, an anti-rotation preventing means (not shown) is arranged on the fixed scroll side.

According to this embodiment, the same operation and effect as those of the embodiment shown in FIG. 1 can be obtained, and both the side acting as a compressor and the side acting as an expander can be forcibly cooled by a cooling fan. Therefore, the cooling effect increases. In addition, since the number of crankshafts is one, no rotation synchronization means or the like is required, and the number of parts can be greatly reduced.

[0069]

As described above, according to the present invention, since each surface of the double-toothed scroll compressor is used for the compressor and the expander, a large-capacity compressor with a small motor capacity can be used. realizable. Further, since a part of the power required for the compressor is recovered by the expander, the power required for the air compressor can be reduced when used in a fuel cell system.

[Brief description of the drawings]

FIG. 1 is a system diagram of a fuel cell system according to the present invention.

FIG. 2 is a longitudinal sectional view of one embodiment of a power recovery type scroll fluid machine according to the present invention.

3 is a vertical sectional view and an upper and lower view of the orbiting scroll shown in FIG. 2;

FIG. 4 is a sectional view taken along line AA of FIG. 2;

FIG. 5 is a side view of the scroll fluid machine shown in FIG. 1;

6 is a perspective view of the scroll fluid machine shown in FIG. 1 and a perspective view of an orbiting scroll section.

FIG. 7 is a longitudinal sectional view of another embodiment of the power recovery type scroll fluid machine according to the present invention.

[Explanation of symbols]

1, 2, fixed scroll, 3, orbiting scroll, 4 ...
Discharge port, 5: suction port, 7: crankshaft, 8: auxiliary crankshaft, 10: thermal expansion difference absorbing mechanism member, 11: timing belt, 12: mirror plate cooling hole, 14: compression working chamber, 15: expansion working chamber , 20, 21 ... suction chamber, 22, 2
3 ... suction port, 24 ... pulley, 30 ... crankshaft,
31, 32: fixed scroll, 33: orbiting scroll,
37: electric motor, 38: fan, 39: compression working chamber, 40
... expansion working chamber, 41 ... discharge port, 42 ... suction port,
50: fuel cell body, 51: electrolyte, 52: hydrogen electrode, 5
3: oxygen electrode, 55: hydrogen chamber, 56: air chamber, 57: air filter, 58: suction flow path, 59: compressor side, 60: power recovery type scroll fluid machine, 61: upstream flow path, 62 ... Downstream flow path, 63: water collector, 64: expander side, 65: silencer, 66: water storage tank, 68: electric valve, 69: electric motor,
72: control device, 75: heater, 77: control panel, 78:
Storage battery, 100: scroll fluid machine.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01M 8/06 H01M 8/06 K (72) Inventor Kazuaki Shiiki 390 Muramatsu, Shimizu, Shizuoka Prefecture Hitachi, Ltd. F term in the industrial equipment group of the factory (reference) 3H029 AA02 AA09 AA16 AA23 AB02 BB12 BB42 CC03 CC05 CC07 CC08 CC27 CC47 3H039 AA01 AA14 BB13 BB28 CC02 CC03 CC08 CC17 CC32 CC34 CC49 5H027 AA06 DD00

Claims (7)

[Claims] An orbiting scroll having a mirror plate and spiral wraps formed on both sides of the mirror plate; and a pair of fixed scrolls having a wrap meshing with the wrap of the orbiting scroll. A power recovery type scroll fluid machine wherein the spiral directions of the formed wraps are opposite to each other. 2. A discharge port for compressed air compressed by the power recovery type scroll fluid machine is formed at one central portion of the pair of fixed scrolls, and the other fixed scroll is provided with the power recovery type fluid machine. 2. The power recovery type scroll fluid machine according to claim 1, wherein a suction port for supplying a gas having a pressure higher than the atmospheric pressure is formed. 3. The apparatus according to claim 1, further comprising a plurality of crankshafts for orbiting the orbiting scroll.
3. The power recovery scroll fluid machine according to 2. 4. A crankshaft for orbiting the orbiting scroll is held at a substantially central portion of the orbiting scroll, and cooling fans are attached to both ends of the crankshaft. The power recovery type scroll fluid machine according to the above. 5. A means for injecting water into a working chamber formed by a wrap of a fixed scroll having a discharge port formed in the central portion and a wrap of an orbiting scroll meshing with the wrap. The power recovery type scroll fluid machine according to any one of claims 2 to 4, wherein: 6. An electric motor, a scroll fluid machine driven by the electric motor, a fuel cell main body for taking out electric power by reacting air compressed by the scroll fluid machine with hydrogen gas, and a fuel cell main body fed from the fuel cell main body. And a flow path for introducing air to the scroll fluid machine, wherein the scroll fluid machine uses one of a double-toothed scroll fluid machine as a compressor and the other as an expander. Battery system. 7. The fuel cell according to claim 6, wherein a collector for collecting moisture is interposed in a flow path for guiding air sent from the fuel cell body to the scroll fluid machine. system.