JP7718248B2 - fuel cell device - Google Patents

Description

The present invention relates to a fuel cell device.

Onboard fuel cell devices equipped with fuel cells are known. Fuel cells generate electricity and produce water through an oxidation-reduction reaction between fuel, such as hydrogen, and oxygen contained in the supplied air. The efficiency of oxidation-reduction reactions decreases at low temperatures. As a result, low-temperature fuel cells wastefully discharge unreacted hydrogen, are unable to generate sufficient electricity, and have a low ability to warm up themselves. Furthermore, onboard fuel cell devices may be exposed to sub-zero temperatures in winter. In such cases, the water inside the device freezes. Therefore, fuel cell devices are equipped with a warm-up mechanism that warms the fuel cell when the device is started.

Japanese Patent Application Laid-Open No. 2000-195533

A conventional fuel cell device includes an air chamber where air reacts, a supply channel that supplies air to the air chamber, and a compressor installed in the supply channel. Conventional fuel cell devices also include a warm-up mechanism that uses the compressor to adiabatically compress and heat the air before inflowing it into the air chamber. Conventional fuel cell devices allow air discharged from the air chamber to flow back into the supply channel, repeatedly adiabatically compressing the air and sufficiently heating the air.

However, in fuel cell devices that are cooled to below freezing, the water produced during power generation freezes inside the device and turns into ice. This ice adheres to the supply channel that supplies air to the fuel cell, the fuel cell's air chamber, and the exhaust channel that discharges air from the fuel cell. When heated air is supplied to the fuel cell, there is a risk that the ice inside the device will peel off and be blown into the air chamber. This blown ice could damage the electrode membrane and gas diffusion layer that face the air chamber.

Therefore, the present invention aims to provide a fuel cell device that can be warmed up with high reliability.

To solve the above problems, the fuel cell device of the present invention comprises a case, a fuel cell housed in the case, a supply path connected to the fuel cell, a blower provided in the supply path that compresses air in the supply path and sends it to the fuel cell, a circulation path connecting the supply path downstream of the blower with the supply path upstream of the blower, a first opening/closing mechanism provided in the supply path downstream of the blower and downstream of the connection between the supply path and the circulation path and that allows or blocks the flow of air in the supply path, a discharge path connected to the supply path downstream of the blower and upstream of the first opening/closing mechanism and that releases the air into the case, a second opening/closing mechanism provided in the circulation path and that allows or blocks the flow of air in the circulation path, and a third opening/closing mechanism provided in the discharge path and that allows or blocks the flow of air in the discharge path.

The present invention provides a fuel cell device that can be warmed up with high reliability.

1 is a configuration diagram showing a fuel cell device according to an embodiment of the present invention; FIG. 10 is an enlarged view of an air passage in an embodiment of the present invention. 4 is a flowchart showing the operation of the fuel cell device according to the embodiment of the present invention. 3 is a time chart showing the operation of the fuel cell device according to the embodiment of the present invention. 4 is a flowchart showing the operation of a startup process of a controller according to an embodiment of the present invention. (A) A graph showing the temperature change of a fuel cell during operation of a fuel cell device, with time on the horizontal axis and temperature on the vertical axis; (B) a graph showing the temperature change of air in the supply path and circulation path during operation of a fuel cell device, with time on the horizontal axis and temperature on the vertical axis. 4 is a flowchart showing the operation of a warm-up process of a controller according to an embodiment of the present invention. 4 is a flowchart showing the operation of a power generation process of a controller according to an embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

An embodiment of a fuel cell device according to the present invention will be described with reference to Figures 1 to 8. Note that the same or corresponding components are designated by the same reference numerals throughout the drawings.

Figure 1 is a diagram showing the configuration of a fuel cell device according to an embodiment of the present invention.

The fuel cell device 1 includes a case 2 with an internal space. The fuel cell device 1 also includes a fuel cell 3, an air path 4 and a hydrogen path (not shown) connected to the fuel cell 3, a fan 5 that blows air to the fuel cell 3, multiple temperature sensors 6, a controller 7, and a battery 8. These are housed in the case 2. Note that in order to clearly show the main structure, Figure 1 shows only a portion of the fuel cell 3 in cross section.

The case 2 is a closed box-shaped body. The case 2 has multiple through-holes 11 in its wall. The internal space of the case 2 is connected to the external space via the through-holes 11. The case 2 is formed, for example, from a metal plate. However, the case 2 may also be a box-shaped body with a portion open.

The fuel cell 3 has a laminated structure in which at least two plate-shaped separators 13 are stacked. The separators 13 have multiple through-holes (not shown) that penetrate in the stacking direction. The fuel cell 3 has an electrode membrane 14 between a pair of adjacent separators 13, and gas diffusion layers 15, 16 provided on the front and back of the electrode membrane 14, respectively. The fuel cell 3 also has two manifold plates 17 that contact the outer surfaces of the two outermost separators 13, an air chamber 18 and a hydrogen chamber 19 that form part of the internal space of the manifold plate 17, and a catalyst layer (not shown).

The front and back surfaces of the electrode membrane 14 are approximately perpendicular to the stacking direction of the fuel cell 3. The air chamber 18 and hydrogen chamber 19 are spaces defined by the inner wall surface of the manifold plate 17 and are, for example, open on the surface of the manifold plate 17 facing the separator 13. The air chamber 18 faces the gas diffusion layer 15 and, for example, the front surface of the electrode membrane 14, with the separator 13 interposed between them. The hydrogen chamber 19 faces the gas diffusion layer 16 and, for example, the back surface of the electrode membrane 14, with the separator 13 interposed between them.

The hydrogen chamber 19 is connected to a hydrogen passage. The hydrogen chamber 19 is supplied with hydrogen (H ₂ ) gas through the hydrogen passage and discharges the gas after reaction. The air chamber 18 is supplied with air through the air passage 4 and discharges the air after reaction.

The fan 5 is positioned near the fuel cell 3 in the internal space of the case 2. The fan 5 has a discharge surface 21 and a suction surface 22. The discharge surface 21 faces, for example, toward the inner wall surface of the case 2, and the suction surface 22 faces, for example, toward the fuel cell 3, specifically, toward the hydrogen chamber 19 of the fuel cell 3. The fan 5 causes air to flow from the suction surface 22 toward the discharge surface 21, thereby drawing in air around the fuel cell 3 through the suction surface 22 and expelling it from the discharge surface 21. In this way, the fan 5 creates an air flow around the fuel cell 3.

Figure 2 is an enlarged view showing the air passage in an embodiment of the present invention. To clearly show the main structure, Figure 2 omits the relief valve 33.

As shown in Figures 1 and 2, the air path 4 includes a supply path 25 that sends air from within the case 2 to the air chamber 18 of the fuel cell 3, a circulation path 26 that connects, for example, two points on the supply path 25, a discharge path 27 that connects to the supply path 25, and a discharge path 28 that discharges air from the air chamber 18 of the fuel cell 3. The supply path 25, circulation path 26, discharge path 27, and discharge path 28 each include, for example, at least one duct, pipe, hose, or other piping.

The air path 4 also has a blower 29 installed in the supply path 25, an upstream valve 31 installed upstream of the blower 29, a downstream valve 32 installed downstream of the blower 29, and a relief valve 33 installed in the circulation path 26. The blower 29 draws in air from the inlet side and blows out air from the outlet side. As a result, the blower 29 draws in air in the supply path 25 from the upstream valve 31 side, compresses it, and discharges the compressed air to the downstream valve 32 side. The relief valve 33 reduces the air pressure in the circulation path 26 when the air in the circulation path 26 exceeds the set pressure.

Hereinafter, for the sake of convenience, the upper end of any of the pipes that make up the air passage 4 refers to the upstream end of that pipe, and the lower end refers to the downstream end of that pipe.

The upper end of the supply path 25 includes an air inlet, and the lower end of the supply path 25 includes an air outlet. The outlet of the supply path 25 is connected to the air chamber 18 of the fuel cell 3. The inlet of the supply path 25 faces the wall surface of the case 2. The inlet of the supply path 25 is adjacent to, for example, the through-hole 11 of the case 2.

The supply path 25 includes a compression path 34 in which the blower 29 is provided, and an introduction path 35 that includes the lower end of the supply path 25. The upper end of the compression path 34 includes the suction port of the supply path 25. An upstream valve 31 is disposed between this upper end and the blower 29. The lower end of the compression path 34 and the upper end of the introduction path 35 are connected via a downstream valve 32. The lower end of the introduction path 35 includes the discharge port of the supply path 25.

The upper end of the circulation path 26 is connected to the downstream side of the blower 29 of the supply path 25 via a downstream valve 32. The lower end of the circulation path 26 is connected to the upstream side of the blower 29 of the supply path 25 via an upstream valve 31. In this way, the circulation path 26 connects the downstream side of the blower 29 of the supply path 25 with the upstream side of the blower 29.

The upper end of the discharge path 27 is connected to the supply path 25 downstream of the blower 29 via a downstream valve 32. The lower end of the discharge path 27 is the outlet of the discharge path 27. The lower end of the discharge path 27 is preferably located on the fuel cell 3 side. Furthermore, the lower end of the discharge path 27 is specifically located on the air chamber 18 side of the fuel cell 3. Furthermore, the lower end of the discharge path 27 is specifically located around the fuel cell 3 and away from the fan 5.

The upstream valve 31 is, for example, an electromagnetic three-way valve. The upstream valve 31 opens and closes at the supply path 25 and at the lower end of the circulation path 26. Note that the upstream valve 31 may also be multiple valves that open and close the supply path 25 and the circulation path 26 individually.

As shown in FIG. 2, the upstream valve 31 has three ports 36a, 36b, and 36c. When opened, the upstream valve 31 connects ports 36a and 36b, and ports 36c and 36b. Ports 36a and 36b are connected to the supply path 25. Specifically, port 36a is connected upstream of port 36b, and port 36b is connected upstream of the blower 29. Port 36c is connected to the lower end of the circulation path 26. Port 36c is located, for example, between ports 36a and 36b. Port 36a is located closer to the upper end of the supply path 25 than ports 36b and 36c.

The upstream valve 31 has an upstream opening/closing mechanism 38. The upstream opening/closing mechanism 38 includes a first upstream opening/closing mechanism 39 that controls the flow of air between ports 36a and 36b, and a second upstream opening/closing mechanism 41 that controls the flow of air between ports 36c and 36b. The first upstream opening/closing mechanism 39 is located upstream of the second upstream opening/closing mechanism 41 on the supply path 25.

The upstream first opening/closing mechanism 39 allows or blocks the flow of air between ports 36a and 36b, i.e., the portion of the supply path 25 upstream of the blower 29. Specifically, the upstream first opening/closing mechanism 39 allows or blocks the flow of air from the upper end of the supply path 25 to the inlet side of the blower 29.

The upstream second opening/closing mechanism 41 allows or blocks the flow of air between port 36c and port 36b, that is, between the lower end of the circulation path 26 and the upstream side of the blower 29 of the supply path 25. In particular, the upstream second opening/closing mechanism 41 allows or blocks the flow of air from the lower end of the circulation path 26 to the inlet side of the blower 29.

The downstream valve 32 is, for example, an electromagnetic four-way valve. The downstream valve 32 opens and closes at the supply path 25, at the upper end of the circulation path 26, and at the upper end of the discharge path 27. Note that the downstream valve 32 may be multiple valves that individually open and close the supply path 25, the circulation path 26, and the discharge path 27.

The downstream valve 32 has four ports 37a, 37b, 37c, and 37d. When opened, the downstream valve 32 connects ports 37a and 37b, ports 37a and 37c, and ports 37a and 37d. Ports 37a and 37b are connected to the supply path 25. Specifically, port 37a is connected downstream of the blower 29, and port 37b is connected downstream of port 37a. Port 37c is connected to the upper end of the circulation path 26, and port 37d is connected to the upper end of the discharge path 27. Ports 37c and 37d are located, for example, between ports 37a and 37b. Port 37b is located downstream of ports 37a, 37c, and 37d in the supply path 25.

The downstream valve 32 has a downstream opening and closing mechanism 42. The downstream opening and closing mechanism 42 includes a downstream first opening and closing mechanism 43 that controls the flow of air between ports 37a and 37b, a downstream second opening and closing mechanism 44 that controls the flow of air between ports 37a and 37c, and a downstream third opening and closing mechanism 45 that controls the flow of air between ports 37a and 37d. The downstream first opening and closing mechanism 43 is located downstream of the downstream second opening and closing mechanism 44 and the downstream third opening and closing mechanism 45 on the supply path 25.

The downstream first opening/closing mechanism 43 allows or blocks the flow of air between ports 37a and 37b, i.e., the portion of the supply path 25 downstream of the blower 29. Specifically, the downstream first opening/closing mechanism 43 allows or blocks the flow of air from the outlet side of the blower to the lower end of the supply path 25.

The downstream second opening/closing mechanism 44 allows or blocks the flow of air between ports 37a and 37c, that is, between the downstream side of the blower 29 of the supply path 25 and the upper end of the circulation path 26. In particular, the downstream second opening/closing mechanism 44 allows or blocks the flow of air from the outlet side of the blower 29 to the upper end of the circulation path 26. The downstream second opening/closing mechanism 44 also allows or blocks the flow of air in the circulation path 26.

The downstream third opening and closing mechanism 45 allows or blocks the flow of air between port 37a and port 37d, that is, between the downstream side of the blower 29 of the supply path 25 and the upper end of the discharge path 27. In particular, the downstream third opening and closing mechanism 45 allows or blocks the flow of air from the outlet side of the blower 29 to the upper end of the discharge path 27. The downstream third opening and closing mechanism 45 also allows or blocks the flow of air through the discharge path 27.

Such an upstream opening/closing mechanism 38 and downstream opening/closing mechanism 42 form a starting flow path 47, a circulation flow path 48, a discharge flow path 49, and a supply flow path 51 in the supply path 25, circulation path 26, and discharge path 27.

The startup flow path 47 is the flow path used when the fuel cell device 1 is started. Air flows through the startup flow path 47, for example, as indicated by the solid arrows in FIG. 2 . This startup flow path 47 is a flow path formed by the portion of the supply path 25 from the suction port to the downstream valve 32 and the circulation path 26, and is formed by opening the upstream first opening/closing mechanism 39, the upstream second opening/closing mechanism 41, and the downstream second opening/closing mechanism 44, and closing the downstream first opening/closing mechanism 43 and the downstream third opening/closing mechanism 45. By closing the downstream first opening/closing mechanism 43 and the downstream third opening/closing mechanism 45, the startup flow path 47 is isolated from the inlet path 35 and the discharge path 27, which are connected to the air chamber 18.

The circulation flow path 48 is a flow path for circulating air and repeatedly compressing it with the blower 29. In the circulation flow path 48, air flows, for example, as indicated by the dashed arrows in FIG. 2 . This circulation flow path 48 is a closed flow path formed by the portion of the supply path 25 from the upstream valve 31 to the downstream valve 32 and the circulation path 26, and is formed by opening the upstream second opening/closing mechanism 41 and the downstream second opening/closing mechanism 44 and closing the upstream first opening/closing mechanism 39, the downstream first opening/closing mechanism 43, and the downstream third opening/closing mechanism 45. Closing the upstream first opening/closing mechanism 39, the downstream first opening/closing mechanism 43, and the downstream third opening/closing mechanism 45 separates the circulation flow path 48 from the upper end of the supply path 25, the inlet path 35, and the outlet path 27.

The discharge flow path 49 is a flow path for discharging air from the air paths 4, such as the supply path 25, into the case 2. In the discharge flow path 49, air flows, for example, as indicated by the dashed-two-dot arrows in FIG. 2 . This discharge flow path 49 is a flow path that includes the portion from the suction port of the supply path 25 to the downstream valve 32, the circulation path 26, and the discharge path 27, and is formed by opening the upstream first opening/closing mechanism 39, the upstream second opening/closing mechanism 41, the downstream second opening/closing mechanism 44, and the downstream third opening/closing mechanism 45, and closing the downstream first opening/closing mechanism 43. Closing the downstream first opening/closing mechanism 43 separates the discharge flow path 49 from the introduction path 35 that connects to the air chamber 18.

The supply flow path 51 is a flow path for supplying air to the air chamber 18 of the fuel cell 3. Air flows through the supply flow path 51, for example, as indicated by the dashed arrow in FIG. 2 . This supply flow path 51 is a flow path from the intake port to the discharge port of the supply path 25, and is formed by opening the upstream first opening/closing mechanism 39 and the downstream first opening/closing mechanism 43 and closing the upstream second opening/closing mechanism 41, the downstream second opening/closing mechanism 44, and the downstream third opening/closing mechanism 45. Closing the upstream second opening/closing mechanism 41, the downstream second opening/closing mechanism 44, and the downstream third opening/closing mechanism 45 isolates the supply flow path 51 from the circulation path 26 and the discharge path 27.

The exhaust path 28 has an air intake port at its upper end and an air exhaust port at its lower end. The intake port of the exhaust path 28 is connected to the air chamber 18 of the fuel cell 3. The intake port of the exhaust path 28 is spaced apart from the exhaust port of the supply path 25, with the air chamber 18 interposed between them. The lower end of the exhaust path 28 may be connected to a portion of the supply path 25, for example, or may be located within the case 2.

As shown in FIG. 1, the battery 8 can supply power to the controller 7 or to devices external to the fuel cell device 1. The battery 8 is preferably provided near the supply path 25 inside the case 2. The battery 8 is, for example, a lithium (Li) ion battery.

The multiple temperature sensors 6 include a first temperature sensor 54 that detects the temperature of the fuel cell 3, a second temperature sensor 55 that detects the temperature of the air in the circulation path 26, and a third temperature sensor 56 that detects the temperature of the air inside the case 2. The first temperature sensor 54, second temperature sensor 55, and third temperature sensor 56 detect the temperatures of their respective objects and generate temperature information d1, d2, and d3.

The first temperature sensor 54 preferably detects the temperature of the fuel cell 3 at the center of the fuel cell 3, for example. The second temperature sensor 55 preferably detects the temperature of the air at the lower end of the circulation path 26, and preferably detects the temperature of the air downstream of the relief valve 33 of the circulation path 26. The third temperature sensor 56 preferably detects the temperature of the air near the fan 5 or the fuel cell 3, and may detect the temperature of the air near the suction surface 22 of the fan 5. The third temperature sensor 56 may also detect the temperature of the fan 5 or the fuel cell 3.

The controller 7 is equipped with a central processing unit (CPU) and a storage device (memory). By reading and executing programs stored in the storage device, the controller 7 functions as, for example, a temperature sensor control unit, a fan control unit, a blower control unit, and an opening/closing mechanism control unit. The controller 7 is supplied with power from the battery 8 within the fuel cell device 1 or another battery (not shown). The controller 7 is electrically connected to the temperature sensor 6, the fan 5, the blower 29, the upstream valve 31, the downstream valve 32, and valves (not shown) that control the flow rate of the discharge channel 28 and the hydrogen channel, for example, via cables, etc.

The controller 7 causes the temperature sensors 6 to detect temperatures and transmit temperature information to the controller 7. Specifically, the controller 7 transmits a temperature detection command r1 to each temperature sensor 6 to detect the temperature, and receives the respective temperature information d1, d2, and d3 from each temperature sensor 6. The controller 7 transmits a drive command r2 and a stop command to the fan 5. The controller 7 transmits a drive command r3 and a stop command to the blower 29.

The controller 7 controls the opening and closing of the upstream opening and closing mechanism 38 and the downstream opening and closing mechanism 42. Specifically, the controller 7 transmits opening and closing information regarding the opening and closing states of the upstream opening and closing mechanism 38 and the downstream opening and closing mechanism 42 to the upstream opening and closing mechanism 38 and the downstream opening and closing mechanism 42. The opening and closing information includes, for example, start opening and closing information r4, circulation opening and closing information r5, discharge opening and closing information r6, and supply opening and closing information r7. The start opening and closing information r4 is opening and closing information for the upstream opening and closing mechanism 38 and the downstream opening and closing mechanism 42 to form a start flow path 47 in the air path 4. The circulation opening and closing information r5 is opening and closing information for the upstream opening and closing mechanism 38 and the downstream opening and closing mechanism 42 to form a circulation flow path 48 in the air path 4. The discharge opening and closing information r6 is opening and closing information for the upstream opening and closing mechanism 38 and the downstream opening and closing mechanism 42 to form a discharge flow path 49 in the air path 4. The supply opening and closing information r7 is opening and closing information for the upstream opening and closing mechanism 38 and the downstream opening and closing mechanism 42 to form a supply flow path 51 in the air path 4.

The operation of a fuel cell device according to an embodiment of the present invention will now be described.

Figure 3 is a flowchart showing the operation of a fuel cell device according to an embodiment of the present invention.

Figure 4 is a time chart showing the opening and closing operations of the upstream opening and closing mechanism and downstream opening and closing mechanism in an embodiment of the present invention.

As shown in Figures 3 and 4, the fuel cell device 1 operates differently during the startup process T1 when the fuel cell device 1 is started, the warm-up process T2 in which air is warmed up inside the fuel cell device 1, and the power generation process T3 in which the fuel cell 3 generates power. The warm-up process T2 includes one or more warm-up cycles T4. The warm-up cycle T4 includes a compression process T5 in which air is adiabatically compressed and heated, and a discharge process T6 in which the heated air is discharged into the case 2. Note that Figure 4 illustrates an example in which the warm-up cycle T4 is performed twice during the warm-up process T2.

Figure 5 is a flowchart showing the operation of the startup process of a controller according to an embodiment of the present invention.

As shown in Figure 5, first, during the start-up process T1, the controller 7 is started by an operation such as starting the engine by the driver (step S1). The controller 7 places the temperature sensor 6, fan 5, blower 29, upstream valve 31, downstream valve 32, etc. in an energized or energizable state. The controller 7 sends a temperature detection command r1 to the first temperature sensor 54. The first temperature sensor 54 acquires temperature information d1 of the fuel cell 3, and the controller 7 receives this temperature information d1 (step S2).

As shown in Figures 2 and 5, the controller 7 then transmits startup opening/closing information r4 to the upstream opening/closing mechanism 38 and the downstream opening/closing mechanism 42 to form the startup flow path 47 (step S3). As a result, the upstream opening/closing mechanism 38 and the downstream opening/closing mechanism 42 switch to a predetermined opening/closing state that forms the startup flow path 47 in the air path 4, and the startup flow path 47 is formed in the air path 4.

Next, the controller 7 sends a drive command r3 to the blower 29 (step S4). This activates the blower 29, sending air from the upstream side of the blower 29 to the downstream side through the start-up flow path 47. Therefore, the air in the start-up flow path 47 flows into the start-up flow path 47 from the suction port of the supply path 25 and circulates within the start-up flow path 47, without flowing into the introduction path 35 or the discharge path 27. Therefore, even if ice adheres to the inner wall surface of the start-up flow path 47, the ice detached by the air flow will not be blown into the air chamber 18 from the introduction path 35. As shown by the solid arrows in Figure 2, the air flow F1 in the start-up flow path 47 specifically flows in from the suction port of the supply path 25 and passes through the upstream first opening/closing mechanism 39, the blower 29, the downstream second opening/closing mechanism 44, the circulation path 26, and the upstream second opening/closing mechanism 41.

Figure 6(A) is a graph showing the temperature change of the fuel cell during operation of the fuel cell device, with time on the horizontal axis and temperature on the vertical axis. Figure 6(B) is a graph showing the temperature change of the air in the supply path or circulation path during operation of the fuel cell device, with time on the horizontal axis and temperature on the vertical axis. Figures 6(A) and 6(B) illustrate the case where the warm-up cycle T4 is performed twice, in line with Figure 4.

As shown in FIGS. 5 and 6A, the controller 7 then determines whether the temperature information d1 from the first temperature sensor 54 is equal to or lower than a first set temperature t1 (step S5). The first set temperature t1 is, for example, 0 degrees Celsius. If the temperature of the fuel cell 3 detected by the first temperature sensor 54 is equal to or lower than the first set temperature t1, the water ( _H2O ) remaining in the air passage 4 and the air chamber 18 of the fuel cell 3 may be frozen, and the power generation efficiency of the fuel cell 3 may be low. Therefore, if the controller 7 determines that the temperature information d1 from the first temperature sensor 54 is equal to or lower than the first set temperature t1, the fuel cell device 1 terminates the startup process T1 and transitions to a warm-up process T2. If the controller 7 determines that the temperature information d1 from the first temperature sensor 54 is higher than the first set temperature t1, the fuel cell device 1 terminates the startup process T1 and transitions to a power generation process T3.

Figure 7 is a flowchart showing the operation of the warm-up process of a controller in an embodiment of the present invention.

As shown in Figures 2 and 7, during the warm-up process T2, the fuel cell device 1 first transitions to the compression process T5 of the warm-up cycle T4. During the compression process T5, the controller 7 first transmits circulation opening/closing information r5 to the upstream opening/closing mechanism 38 and the downstream opening/closing mechanism 42 (step S6). As a result, the upstream opening/closing mechanism 38 and the downstream opening/closing mechanism 42 switch to a predetermined opening/closing state that forms a circulation flow path 48 in the air path 4, and the circulation flow path 48 is formed in the air path 4.

The air in the circulation flow path 48 is circulated through the closed circulation flow path 48 by the blower 29, and does not flow into the upper end of the supply path 25, the inlet path 35, or the discharge path 27. As shown by the dashed-dotted arrows in FIG. 2 , the air flow F2 in the circulation flow path 48 passes through, for example, the blower 29, the downstream second opening/closing mechanism 44, the circulation path 26, and the upstream second opening/closing mechanism 41 before circulating through the circulation flow path 48. As shown in FIG. 6(B) , during this compression process T5, the air in the circulation flow path 48 is adiabatically compressed and its temperature rises. Furthermore, as the temperature of the air in the circulation flow path 48 rises, heat is transferred to the supply path 25 and the circulation path 26 in which the circulation flow path 48 is formed. Furthermore, heat is gradually transferred to the inlet path 35 and the discharge path 27, and, for example, to the air in the case 2, the fuel cell 3, and the battery 8. As shown in Figure 6 (B), the heat from the air whose temperature has increased in the circulation flow path 48 gradually warms up the battery 8 and fuel cell 3, and gradually warms the air inside the case 2.

On the other hand, if the air pressure in the circulation flow path 48 exceeds a predetermined pressure, such as the allowable upper limit pressure, some of the air in the circulation flow path 48 is released by the relief valve 33, reducing the pressure. As a result, the air pressure in the circulation flow path 48 does not exceed the allowable upper limit pressure, for example. In this case, the air released from the relief valve 33 slightly warms the air in the case 2.

As shown in FIGS. 2 and 7, after a certain period of time has elapsed since the circulation opening/closing information r5 was sent, the controller 7 sends a temperature detection command r1 to the second temperature sensor 55. The second temperature sensor 55 then acquires temperature information d2 of the air in the circulation path 26 and sends this temperature information d2 to the controller 7 (step S7). Next, the controller 7 determines whether the temperature information d2 from the second temperature sensor 55 is equal to or higher than the second set temperature t2 (step S8). As shown in FIG. 6(B), the second set temperature t2 is higher than the first set temperature t1. When the air in the circulation path 48 having a temperature equal to or higher than the second set temperature t2 is released into the internal space of the case 2, it effectively warms the air in the case 2, thereby effectively warming the fuel cell 3, fan 5, and battery 8.

Therefore, when the controller 7 determines that the temperature information d2 from the second temperature sensor 55 is equal to or higher than the second set temperature t2, the fuel cell device 1 terminates the compression process T5 and transitions to the discharge process T6. When the controller 7 determines that the temperature information d2 from the second temperature sensor 55 is lower than the second set temperature t2, the compression process T5 continues for a certain period of time to adiabatically compress the air in the circulation flow path 48 and raise its temperature. The controller 7 then again sends a temperature detection command r1 to the second temperature sensor 55 to obtain the temperature information d2 (step S7) and determines whether the temperature information d2 is equal to or higher than the second set temperature t2 (step S8). In this way, the compression process T5 continues until the controller 7 determines that the temperature of the air in the circulation flow path 48 is equal to or higher than the second set temperature t2.

As shown in Figures 2 and 7, during the discharge process T6, the controller 7 first transmits discharge opening/closing information r6 to the upstream opening/closing mechanism 38 and the downstream opening/closing mechanism 42 (step S9). As a result, the upstream opening/closing mechanism 38 and the downstream opening/closing mechanism 42 switch to a predetermined open/close state that forms a discharge flow path 49 in the air path 4, and the discharge flow path 49 is formed in the air path 4.

As shown in Figures 2 and 7, the air in the discharge flow path 49, whose temperature has risen to or exceeds the second set temperature t2 during the compression process T5, flows through the discharge flow path 49 together with the air inside the case 2 that has flowed in from the intake port of the supply path 25 because the blower 29 is driven by the discharge flow path 49. At this time, the air in the discharge flow path 49 does not flow into the introduction path 35. As shown by the dashed-dotted arrow in Figure 2, the air flow F3 in the discharge flow path 49 includes a main flow F4 and a diverted flow F5. The main flow F4 passes through the upstream first opening/closing mechanism 39, the blower 29, the downstream third opening/closing mechanism 45, and the discharge path 27 before being released from the outlet of the discharge path 27. The diverted flow F5, for example, branches off from the main flow at the downstream valve 32, passes through the downstream second opening/closing mechanism 44, the circulation path 26, and the upstream second opening/closing mechanism 41, and rejoins the main flow F4 at the upstream valve 31.

The air released from the discharge flow path 49 is diffused within the case 2, effectively raising the temperature of the air within the case 2. As shown in Figure 6(A), this facilitates heat transfer to the fuel cell 3, discharge path 28, and inlet path 35. Furthermore, because the lower end of the discharge path 27 is located on the fuel cell 3 side, specifically around the fuel cell 3, the temperature of the fuel cell 3 and the air around it tends to rise. As shown in Figure 6(B), the temperature of the air in the discharge flow path 49 drops as warm air is released and air from within the case 2 continues to flow in through the intake port of the supply path 25.

As shown in FIG. 7 , the controller 7 then sends a temperature detection command r1 to the third temperature sensor 56, which then acquires temperature information d3 of the air inside the case 2. The controller 7 then acquires this temperature information d3 (step S10). Next, the controller 7 determines whether the temperature information d3 from the third temperature sensor 56 is equal to or higher than the third set temperature t3 (step S11). The third set temperature t3 is, for example, higher than the first set temperature t1 and lower than the second set temperature t2. When the air inside the case 2, which has a temperature equal to or higher than the third set temperature t3, is forced to flow around the fuel cell 3 by the fan 5, it can effectively provide heat to the fuel cell 3.

For this reason, if the controller 7 determines that the temperature information d3 from the third temperature sensor 56 is equal to or higher than the third set temperature t3, the controller 7 sends a drive command r2 to the fan 5 (step S12). This causes the fan 5 to blow air onto the fuel cell 3, providing heat to the fuel cell 3. If the controller 7 determines that the temperature information d3 from the third temperature sensor 56 is lower than the third set temperature t3, the fuel cell device 1 ends the discharge process T6 and moves on to the next warm-up cycle T4, similarly performing the compression process T5 and the discharge process T6. In this way, this warm-up cycle T4 is repeated until the controller 7 determines that the temperature of the air inside the case 2 is equal to or higher than the third set temperature t3.

After a predetermined period of time has elapsed since the drive command r2 was sent to the fan 5, the controller 7 sends a temperature detection command r1 to the first temperature sensor 54. The first temperature sensor 54 then acquires temperature information d1 from the fuel cell 3 and transmits this temperature information d1 to the controller 7 (step S13). Next, the controller 7 determines whether the temperature information d1 from the first temperature sensor 54 is higher than a fourth set temperature t4 (step S14). As shown in FIG. 6A, the fourth set temperature t4 may be the same as or higher than the first set temperature t1. If the temperature of the fuel cell 3 is higher than the fourth set temperature t4, it can be predicted that the water remaining in the air passages 4, such as the exhaust passage 28 and the inlet passage 35, and in the air chamber 18 of the fuel cell 3 is liquid. Furthermore, if the temperature of the fuel cell 3 is higher than the fourth set temperature t4, it can be predicted that the fuel cell 3 has warmed up and that the air passage 4 and the air in the case 2 have warmed up.

For this reason, if the controller 7 determines that the temperature information d1 from the first temperature sensor 54 is higher than the fourth set temperature t4, the fuel cell device 1 ends the warm-up process T2 and transitions to the power generation process T3. If the controller 7 determines that the temperature information d1 from the first temperature sensor 54 is equal to or lower than the fourth set temperature t4, the fuel cell device 1 ends the discharge process T6 and transitions to the next warm-up cycle T4, and similarly performs the compression process T5 and discharge process T6.

Figure 8 is a flowchart showing the operation of the power generation process of a controller in an embodiment of the present invention.

As shown in Figures 2 and 8, during power generation process T3, the controller 7 first transmits supply opening/closing information r7 to the upstream opening/closing mechanism 38 and the downstream opening/closing mechanism 42 (step S15). As a result, the upstream opening/closing mechanism 38 and the downstream opening/closing mechanism 42 switch to a predetermined opening/closing state that forms a supply flow path 51 in the air path 4, and the supply flow path 51 is formed in the air path 4. In this case, it is preferable that the controller 7, for example, first transmits the supply opening/closing information r7 to the upstream opening/closing mechanism 38, and after the upstream opening/closing mechanism 38 switches to the predetermined opening/closing state, transmits the supply opening/closing information r7 to the downstream opening/closing mechanism 42, and the downstream opening/closing mechanism 42 switches to the predetermined opening/closing state.

Because the blower 29 is driven by the supply flow path 51, the air in the supply flow path 51 flows through the supply flow path 51 along with the air inside the case 2 that flows in through the suction port of the supply path 25. At this time, the air in the supply flow path 51 does not flow, for example, into the circulation path 26 or the discharge path 27. As shown by the dashed arrows in Figure 2, the air flow F6 in the supply flow path 51 passes through the upstream first opening/closing mechanism 39, the blower 29, the downstream first opening/closing mechanism 43, and the introduction path 35. Furthermore, because the air flow F6 in the supply flow path 51 does not enter the upper end of the circulation path 26 or the upper end of the discharge path 27, loss is minimal. Furthermore, the air in the supply flow path 51 flows through the air chamber 18 and the discharge path 28. At this time, the air in the supply flow path 51 pushes the water remaining in the supply flow path 51, the air chamber 18, and the discharge path 28 downstream, causing the water to flow downstream. Water that flows into the air chamber 18 does not damage the gas diffusion layer 15 or electrode membrane 14 even when it passes through the separator 13. In this way, air from inside the case 2 continues to be supplied to the air chamber 18 from the supply flow path 51. The temperature of the air in this supply flow path 51 is higher than the fourth set temperature t4, for example.

Next, the controller 7 starts the flow of hydrogen through the hydrogen path (step S16). This supplies hydrogen to the hydrogen chamber 19, initiating an oxidation-reduction reaction between the hydrogen in the hydrogen chamber 19 and the oxygen in the air chamber 18, and the fuel cell 3 begins generating electricity. For example, when the driver stops the engine, the controller 7 stops the supply of electricity to the temperature sensor 6, fan 5, blower 29, upstream valve 31, downstream valve 32, etc., and stops the flow of hydrogen through the hydrogen path. This marks the end of the power generation process T3 in the fuel cell device 1.

As shown in FIG. 1, the discharge path 27 and downstream third opening/closing mechanism 45 may not be provided, for example. In this case, the fuel cell device 1 is warmed up by heat transfer from the air path 4 in which the circulation path 48 is formed, or the air discharged from the relief valve 33 warms the air inside the case 2. Furthermore, if the discharge path 27 and downstream third opening/closing mechanism 45 are not provided, the fuel cell device 1 may warm up the fuel cell 3 using refrigerant whose heat has been transferred from the circulation path 48, or the fuel cell 3 may be warmed up directly by arranging the circulation path 26 around the fuel cell 3.

Other components, such as the air passage 4, hydrogen passage, and fan 5, other than the fuel cell 3, may be partially uncovered by the case 2 and exposed to the outside. The relief valve 33 is provided in the circulation passage 26, but may also be provided downstream of the upstream first opening/closing mechanism 39 and upstream of the downstream first opening/closing mechanism 43 of the supply passage 25.

The first temperature sensor 54 detects the temperature of the fuel cell 3, but is not limited to this. The first temperature sensor 54 may, for example, detect the temperature of other components within the case 2, preferably other components near the fuel cell 3, or may detect the temperature of the air around these components. The second temperature sensor 55 detects the temperature of the air in the circulation path 26, but is not limited to this. The second temperature sensor 55 may, for example, detect the temperature of the air in the supply path 25, specifically upstream of the blower 29, or may detect the temperature of the circulation path 26 or the supply path 25.

The fuel cell device 1 according to this embodiment includes a supply path 25 connected to the air chamber 18 of the fuel cell 3; a blower 29 provided in the supply path 25 that compresses the air in the supply path 25 and sends it to the fuel cell 3; a circulation path 26 connecting the downstream side of the blower 29 and the upstream side of the supply path 25; and a downstream first opening/closing mechanism 43 provided in the supply path 25 downstream of the blower 29 and downstream of the connection between the supply path 25 and the circulation path 26 that allows or blocks the flow of air in the supply path 25. Therefore, during warm-up operation after startup, for example, the fuel cell device 1 circulates air through the supply path 25 and the circulation path 26, repeatedly performing adiabatic compression. This allows the fuel cell device 1 to efficiently increase the air temperature and warm up.

Furthermore, the fuel cell device 1 adiabatically compresses air in the supply path 25 and circulation path 26 with the downstream first opening/closing mechanism 43 closed. As a result, the fuel cell device 1 heats the air without allowing it to flow into the air chamber 18 of the fuel cell 3. Therefore, when the temperature of the fuel cell 3 is below freezing, for example, ice adhering to the inner wall surfaces of the air path 4 and air chamber 18 is prevented from being detached by air circulation and blown into the air chamber 18. In this way, the fuel cell device 1 can prevent damage to the gas diffusion layer 15 and electrode film 14 facing the air chamber 18 during warm-up operation.

Furthermore, the fuel cell device 1 includes a discharge path 27 connected to the supply path 25 downstream of the blower 29 and upstream of the first downstream opening/closing mechanism 43 to discharge air into the case 2, and a third downstream opening/closing mechanism 45 provided on the discharge path 27 to allow or block the flow of air through the discharge path 27. As a result, the fuel cell device 1 opens the third downstream opening/closing mechanism 45 to discharge heated air from the discharge path 27 into the case 2. As a result, the fuel cell device 1 uses the heated air to warm the fuel cell 3, the air paths 4 downstream of the downstream valve 32, such as the inlet path 35 and outlet path 28, and the air inside the case 2. The supply path 25 also draws in air from the case 2, repeatedly heating and releasing the air, thereby warming the air in stages. In this way, the fuel cell device 1 can be effectively warmed up.

The fuel cell device 1 according to this embodiment also includes a downstream valve 32 that selectively opens and closes in at least three directions. The downstream first opening and closing mechanism 43, downstream second opening and closing mechanism 44, and downstream third opening and closing mechanism 45 are integrally provided on the downstream valve 32. As a result, the fuel cell device 1 is provided with the downstream second opening and closing mechanism 44 and downstream third opening and closing mechanism 45 at the upper end of the circulation path 26 and the upper end of the discharge path 27, respectively. As a result, the fuel cell device 1 can reduce losses in the air flow F6 in the supply flow path 51 and the air flow F3 in the discharge flow path 49.

The fuel cell device 1 according to this embodiment also includes a fan 5 that faces the fuel cell 3 and causes air to flow around the fuel cell 3. The lower end of the discharge path 27 is located on the fuel cell 3 side. This allows the fan 5 to flow heated air around the fuel cell 3, effectively warming up the fuel cell 3.

Furthermore, the fuel cell device 1 according to this embodiment is equipped with a first temperature sensor 54 that detects the temperature of at least a portion of the interior of the case 2. When the temperature detected by the first temperature sensor 54 is equal to or lower than the first set temperature t1, the downstream first opening/closing mechanism 43 and the downstream third opening/closing mechanism 45 are closed, and the downstream second opening/closing mechanism 44 is opened, allowing air to flow through the circulation path 26. When the temperature detected by the first temperature sensor 54 is higher than the first set temperature t1, the downstream third opening/closing mechanism 45 is closed, and the downstream first opening/closing mechanism 43 is opened, allowing air to flow through the fuel cell 3. As a result, the fuel cell device 1 sets the first set temperature t1, for example, as the temperature at which the fuel cell 3 must be warmed up. When the temperature detected by the first temperature sensor 54 is equal to or lower than the first set temperature t1, the fuel cell device 1 circulates air through the supply path 25 and the circulation path 26, repeatedly performing adiabatic compression to warm the air and thereby warm up the fuel cell 3. On the other hand, when the temperature detected by the first temperature sensor 54 is higher than the first set temperature t1, the fuel cell device 1 can start generating electricity by flowing air from the supply path 25 to the fuel cell 3.

Furthermore, in the fuel cell device 1 according to this embodiment, the first temperature sensor 54 detects the temperature of the fuel cell 3. This allows the first set temperature t1 to be accurately set as the temperature at which the fuel cell 3 needs to be warmed up.

Furthermore, the fuel cell device 1 according to this embodiment is equipped with a second temperature sensor 55 that detects the temperature of the air in at least one of the supply path 25 and the circulation path 26. When the temperature detected by the first temperature sensor 54 is equal to or lower than the first set temperature t1 and the temperature detected by the second temperature sensor 55 is equal to or higher than the higher second set temperature t2, the downstream first opening/closing mechanism 43 is closed and the downstream third opening/closing mechanism 45 is opened. The second set temperature t2 is higher than the first set temperature t1. As a result, the fuel cell device 1 sets the second set temperature t2 as a temperature that can effectively warm up the fuel cell 3 when heated air is released from the release path 27, for example. When the temperature detected by the first temperature sensor 54 is equal to or lower than the first set temperature t1 and the temperature detected by the second temperature sensor 55 is equal to or higher than the second set temperature t2, the fuel cell device 1 can effectively warm up the fuel cell 3 by releasing heated air from the release path 27.

Therefore, the fuel cell device 1 according to this embodiment enables highly reliable warm-up.

1...Fuel cell device, 2...Case, 3...Fuel cell, 4...Air passage, 5...Fan, 6...Temperature sensor, 7...Controller, 11...Through-hole, 13...Separator, 14...Electrode membrane, 15, 16...Gas diffusion layer, 17...Manifold plate, 18...Air chamber, 19...Hydrogen chamber, 21...Discharge surface, 22...Suction surface, 25...Supply channel, 26...Circulation channel, 27...Discharge channel, 28...Discharge channel, 29...Supply channel, 29...Blower, 31...Upstream valve, 32...Downstream valve, 33...Relief valve, 34...Compression channel, 35...Inlet channel, 36a-36c...Ports, 37a-37d...Ports, 38...Upstream opening/closing mechanism, 39...Upstream first opening/closing mechanism, 41...Upstream second opening/closing mechanism, 42...Downstream opening/closing mechanism, 43... ...Downstream first switching mechanism, 44...Downstream second switching mechanism, 45...Downstream third switching mechanism, 47...Starting flow path, 48...Circulation flow path, 49...Discharge flow path, 51...Supply flow path, 54...First temperature sensor, 55...Second temperature sensor, 56...Third temperature sensor, d1-d3...Temperature information, F4...Main flow, F5...Diversion flow, Li...Lithium, r1...Temperature detection command, r2, r3...Drive command, r4...Starting switching information, r5...Circulation switching information, r6...Discharge switching information, r7...Supply switching information, S1-S16...Step, t1...First set temperature, t2...Second set temperature, t3...Third set temperature, t4...Fourth set temperature, T1...Starting process, T2...Warm-up process, T3...Power generation process, T4...Warm-up cycle, T5...Compression process, T6...Discharge process

Claims (6)

Case and
a fuel cell housed in the case;
a supply path connected to the fuel cell;
a blower provided in the supply path to compress the air in the supply path and send it to the fuel cell;
a circulation path connecting a downstream side of the blower and an upstream side of the blower in the supply path;
a first opening/closing mechanism that is provided in the supply path downstream of the blower and downstream of a connection between the supply path and the circulation path and that allows or blocks the flow of air in the supply path;
a discharge path connected to the supply path downstream of the blower and upstream of the first opening/closing mechanism, and discharging the air into the case;
a second opening/closing mechanism provided in the circulation path and configured to allow or block the flow of air through the circulation path;
a third opening/closing mechanism provided in the discharge path for allowing or blocking the flow of air in the discharge path. a valve that selectively opens and closes in at least three directions;
2. The fuel cell device according to claim 1, wherein the first opening/closing mechanism, the second opening/closing mechanism, and the third opening/closing mechanism are integrally provided on the valve. a fan provided opposite the fuel cell to cause air to flow around the fuel cell;
3. The fuel cell device according to claim 1, wherein a lower end of the discharge path is disposed on the fuel cell side. a first temperature sensor for detecting a temperature in at least a part of the case;
when the temperature detected by the first temperature sensor is equal to or lower than a first set temperature, the first opening/closing mechanism and the third opening/closing mechanism are closed and the second opening/closing mechanism is opened to allow the air to flow through the circulation path;
A fuel cell device described in any one of claims 1 to 3, wherein when the temperature detected by the first temperature sensor is higher than the first set temperature, the third opening and closing mechanism is closed and the first opening and closing mechanism is opened to allow the air to flow through the fuel cell. The fuel cell device described in claim 4, wherein the first temperature sensor detects the temperature of the fuel cell. a second temperature sensor that detects the temperature of the air in at least one of the supply path and the circulation path;
6. A fuel cell device as described in claim 4 or 5, wherein when the temperature detected by the first temperature sensor is equal to or lower than the first set temperature and the temperature detected by the second temperature sensor is equal to or higher than a second set temperature that is higher than the first set temperature, the first opening/closing mechanism is closed and the third opening/closing mechanism is opened.