JP7830282B2 - activation device - Google Patents

Description

This invention relates to an activation device for activating electrolyte membranes and electrode structures for fuel cells.

Traditionally, efforts have been made to mitigate or reduce the impact of climate change, and research and development on _CO2 reduction has been conducted to achieve this. From this perspective, fuel cell vehicles (FCVs) equipped with fuel cells are attracting attention. This is because fuel cell vehicles emit only water vapor and do not emit _CO2 , _NOx , _SOx, etc.

A fuel cell comprises an electrolyte membrane-electrode structure (MEA). The MEA includes an electrolyte membrane made of a solid polymer having a first end face and a second end face, an anode electrode provided on the first end face of the electrolyte membrane, and a cathode electrode provided on the second end face of the electrolyte membrane. That is, the MEA is constructed by sandwiching the electrolyte membrane between the anode electrode and the cathode electrode. The unit cell of the fuel cell is assembled by sandwiching the MEA between a set of separators.

Immediately after assembly, the electrolyte membrane of a unit cell does not have sufficient water content. Therefore, sufficient power generation performance cannot be obtained from this unit cell. To avoid this, the fuel cell is activated before the first operation. Generally, a fuel cell stack, consisting of multiple unit cells stacked together, is activated. In contrast, Patent Document 1 discloses activating individual unit cells. In this case, the fuel cell stack is assembled by stacking the activated unit cells.

Japanese Patent Publication No. 2014-7006

A first gas channel is formed in one of the separators in a pair. A second gas channel is formed in the other of the separators in a pair. During the activation process of the electrolyte membrane/electrode structure (MEA), a moist gas may flow through the first and second gas channels. When the moist gas comes into contact with the anode and cathode electrodes, moisture is imparted to the anode and cathode electrodes, respectively.

When excessive moisture is applied to the anode or cathode electrode, a liquid film forms on the electrode. This is known as flooding. Under these conditions, the wet gas has difficulty penetrating each electrode catalyst of the anode or cathode electrode. In this case, the activation of the electrode catalyst is hindered.

Furthermore, when activation is performed at a high current density, the partial pressure of the activated gas decreases and the partial pressure of water vapor increases, particularly near the gas outlet of the second gas channel. Therefore, flooding is likely to occur near the gas outlet of the second gas channel. To avoid this, for example, the amount of moisture added to the humidified gas can be reduced, thereby lowering the relative humidity of the humidified gas. However, in this case, the activation efficiency of the MEA decreases.

The present invention aims to solve the problems described above.

According to one embodiment of the present invention, an activation device for activating an electrolyte membrane/electrode structure in which an electrolyte membrane is sandwiched between an anode electrode and a cathode electrode constituting a fuel cell comprises a plurality of jigs stacked with the electrolyte membrane/electrode structure sandwiched between them, a heat pipe provided on each of the plurality of jigs, a heat supply unit for supplying heat to the heat pipe, a control unit for controlling the heat supplied from the heat supply unit to the heat pipe, a first activation gas supply source for supplying a first activation gas, and a second activation gas supply source for supplying a second activation gas, wherein each of the plurality of jigs has a first surface facing the anode electrode, a second surface facing the cathode electrode, a first inlet extending along the stacking direction of the plurality of jigs and into which the first activation gas flows, and a second inlet extending along the first surface Furthermore, an activation device is provided, comprising: a first channel communicating with the first inlet; a first outlet extending along the stacking direction and through which the first activated gas flowing through the first channel flows out; a second inlet extending along the stacking direction and through which the second activated gas flows in; a second channel extending along the second surface and communicating with the second inlet; and a second outlet extending along the stacking direction and through which the second activated gas flowing through the second channel flows out. The first and second channels extend in directions parallel to or intersecting the heat pipe, and when viewing the first or second surface of each of the plurality of jigs, the first inlet, first outlet, second inlet, and second outlet are spaced apart from each other in the direction of extension of the heat pipe and in directions perpendicular to the direction of extension.

As can be understood from the above, the first inlet, first outlet, second inlet, and second outlet are formed individually in the jig. That is, the formation locations of the first inlet, first outlet, second inlet, and second outlet do not coincide with each other. Furthermore, the first and second flow paths are independent gas flow paths and do not communicate with each other.

In this invention, a heat pipe is provided in the jig to adjust the temperatures of the first and second activated gases. The heat pipe has a high response speed to heat input or output. Therefore, by exchanging heat between the heat pipe and the first and second activated gases, the temperatures of the first and second activated gases can be rapidly adjusted. That is, the temperatures of the first and second activated gases are adjusted to a predetermined range.

This ensures that the liquid water levels in the first and second channels of the jig are maintained within an appropriate range. Therefore, according to the present invention, it is possible to appropriately moisten and activate multiple electrolyte membrane and electrode structures while avoiding flooding in the first and second channels.

Furthermore, the first inlet, first outlet, second inlet, and second outlet are spaced apart from each other within the first and second surfaces of the jig. This allows for miniaturization of the jig.

Figure 1 is a schematic system diagram of the activation device according to this embodiment. Figure 2 is an enlarged cross-sectional view of the main part of the activation device. Figure 3 is a schematic front view of the jig constituting the activation device, viewed from the side facing the anode electrode of the electrolyte membrane and electrode structure. Figure 4 is a schematic front view of the jig constituting the activation device, viewed from the side facing the cathode electrode of the electrolyte membrane and electrode structure. Figure 5 is a cross-sectional view taken along the line V-V in Figure 4. Figure 6 is a schematic front view of a jig in another embodiment, viewed from the side facing the anode electrode of the electrolyte membrane/electrode structure. Figure 7 is a schematic front view of a jig in another embodiment, viewed from the side facing the cathode electrode of the electrolyte membrane/electrode structure.

Figure 1 is a schematic system diagram of the activation device 40 according to this embodiment. The activation device 40 includes a plurality of jigs 42 that sandwich the electrolyte membrane/electrode structure 10. First, the electrolyte membrane/electrode structure 10 will be briefly described with reference to Figure 2. In the following description, the electrolyte membrane/electrode structure may also be referred to as "MEA".

The MEA 10 comprises an electrolyte membrane 12 made of a solid polymer. Examples of solid polymers include perfluorosulfonic acid. The electrolyte membrane 12 is sandwiched between the cathode electrode 14 and the anode electrode 16. The cathode electrode 14 has a first electrode catalyst layer 18 containing an electrode catalyst and a first gas diffusion layer 20 for supplying gas to the first electrode catalyst layer 18. The anode electrode 16 has a second electrode catalyst layer 22 containing an electrode catalyst and a second gas diffusion layer 24 for supplying gas to the second electrode catalyst layer 22. The MEA 10 is a thin film.

Next, the activation device 40 will be described with reference to Figures 1 to 6. As shown in Figures 1 and 2, the activation device 40 is equipped with multiple jigs 42. The jigs 42 are roughly plate-shaped and thin-walled. By alternately stacking one jig 42 and one MEA 10, a laminate 44 is formed in which an MEA 10 is sandwiched between two jigs 42. Therefore, in the laminate 44, two MEA 10s abut against both end faces of one jig 42.

For convenience, in Figure 2, the MEA 10 located below the jig 42 will be referred to as the first MEA 10a, and the MEA 10 located above the jig 42 will be referred to as the second MEA 10b. The jig 42 has a first surface 46 facing the anode electrode 16 of the first MEA 10a and a second surface 48 facing the cathode electrode 14 of the second MEA 10b. The other MEA 10 is also positioned between the two jigs 42, similar to the first MEA 10a and the second MEA 10b, with the cathode electrode 14 facing downwards in Figure 2 and the anode electrode 16 facing upwards in Figure 2.

Figure 3 is a schematic overall front view of the jig 42 as seen from the first surface 46. Figure 4 is a schematic overall front view of the jig 42 as seen from the second surface 48. As shown in Figures 1 to 4, the jig 42 has two base plates 50a and 50b. Multiple heat pipes 52 are sandwiched between the two base plates 50a and 50b. The heat pipes 52 extend in a direction perpendicular to the stacking direction of the laminate 44.

A heat supply unit 54, consisting of a heater or Peltier element, is connected to the heat pipe 52. In this embodiment, the heat supply unit 54 is positioned at the end of the heat pipe 52 in the direction of its extension. The heat supply unit 54 applies heat to the heat pipe 52.

The two base plates 50a and 50b have a first inlet 56, a first outlet 58, a second inlet 60, and a second outlet 62 formed at their four corners, respectively. The first inlet 56, first outlet 58, second inlet 60, and second outlet 62 are spaced apart from each other in the direction of extension of the heat pipe 52. They are also spaced apart from each other in the direction perpendicular to the direction of extension of the heat pipe 52. Typically, the first inlet 56 and first outlet 58 are diagonally opposite each other. Similarly, the second inlet 60 and second outlet 62 are also diagonally opposite each other.

In the laminate 44, the first inlets 56 of multiple jigs 42 are connected to each other along the stacking direction. This forms a first inlet passage 56a through which multiple first inlets 56 are connected. Similarly, the first outlets 58 of multiple jigs 42 are also connected to each other along the stacking direction of the laminate 44. As a result, as shown in Figure 5, a first outlet passage 58a is formed through which multiple first outlets 58 are connected. Furthermore, the second inlets 60 and second outlets 62 are also connected to each other along the stacking direction of the laminate 44. As a result, a second inlet passage 60a is formed through which multiple second inlets 60 are connected, and a second outlet passage 62a is formed through which multiple second outlets 62 are connected.

The first inlet passage 56a and the first outlet passage 58a are flow passages for flowing the first activated gas along the stacking direction of the laminate 44. The first inlet passage 56a (first inlet 56) and the first outlet passage 58a (first outlet 58) are connected via the first flow path 64 shown in Figure 3. The second inlet passage 60a and the second outlet passage 62a are flow passages for flowing the second activated gas along the stacking direction of the laminate 44. The second inlet passage 60a (second inlet 60) and the second outlet passage 62a (second outlet 62) are connected via the second flow path 72 shown in Figure 4. The first inlet passage 56a is not connected to the second inlet passage 60a and the second outlet passage 62a. Similarly, the second inlet passage 60a is not connected to the first inlet passage 56a and the first outlet passage 58a.

As can be seen from Figure 2, the base plate 50a forms a first surface 46 facing the anode electrode 16 (second electrode catalyst layer 22) of the first MEA 10a. As shown in Figure 3, the first surface 46 has a first channel 64 that is recessed along the stacking direction and extends along the surface direction of the first surface 46. The first channel 64 has one first distribution channel 66, a plurality of first branch channels 68, and one first aggregation channel 70. The first distribution channel 66 is connected to the first inlet 56 (first inlet connecting passage 56a). The plurality of first branch channels 68 branch off from the first distribution channel 66. The plurality of first branch channels 68 converge at the first aggregation channel 70. The first aggregation channel 70 is connected to the first outlet 58 (first outlet connecting passage 58a). In this way, the first inlet 56 and the first outlet 58 are in communication via the first channel 64.

As can be seen from Figure 2, the base plate 50b forms a second surface 48 facing the cathode electrode 14 (first electrode catalyst layer 18) of the second MEA 10b. As shown in Figure 4, the second surface 48 has a second channel 72 that is recessed along the stacking direction and extends along the surface direction of the second surface 48. The second channel 72 has a plurality of second branch passages 74. The plurality of second branch passages 74 are each connected to, for example, the second inlet 60 (second inlet connecting passage 60a). Alternatively, as shown in the illustrated example, a second distribution passage 76 may be interposed between the second inlet 60 and two or more second branch passages 74. The plurality of second branch passages 74 are each connected to, for example, the second outlet 62 (second outlet connecting passage 62a). Alternatively, as shown in the illustrated example, a second collection passage 78 may be interposed between two or more second branch passages 74 and the second outlet 62.

As shown in Figures 3 and 4, in this embodiment, the first branch 68 and the second branch 74 are perpendicular to the heat pipe 52.

Multiple second branch lines 74 are provided with a first heat storage section 80 and a second heat storage section 82, respectively. In this case, the first heat storage section 80 and the second heat storage section 82 each consist of a recess that starts from the second branch line 74 and is recessed along the stacking direction of the laminate 44. That is, in this case, the first heat storage section 80 and the second heat storage section 82 are spaces that extend from the second branch line 74 toward the stacking direction of the laminate 44.

The volume of the second heat storage unit 82 is larger than the volume of the first heat storage unit 80. That is, the heat storage units are arranged in order of increasing volume from the second inlet 60 to the second outlet 62. The second heat storage unit 82 captures a larger amount of the second humid gas than the first heat storage unit 80.

The number of heat storage units provided in one second branch circuit 74 is not particularly limited to the two shown in the illustrated example. Providing a heat storage unit in the second branch circuit 74 is not mandatory. Furthermore, a heat storage unit may also be provided in the first branch circuit 68.

The base plates 50a and 50b are provided with a first electrical terminal 84 and a second electrical terminal 86, respectively.

As shown in Figure 1, the activation device 40 includes a first gas line 90. A hydrogen gas supply unit 92 and a nitrogen gas supply unit 94 are connected to one end of the first gas line 90 via a first three-way valve 96. The hydrogen gas supply unit 92 is, for example, a hydrogen gas tank. The nitrogen gas supply unit 94 is, for example, a nitrogen gas tank. A first humidifier 98 is provided in the first gas line 90. The hydrogen gas supply unit 92 and the first humidifier 98 constitute the first humidifying gas supply unit, and the hydrogen gas to which moisture has been added by the first humidifier 98 is the first humidifying gas, acting as the first activation gas.

The other end of the first gas line 90 is connected to the first inlet passage 56a via a pipe fitting. The first humid gas (humid hydrogen gas) flowing from the other end of the first gas line 90 into the first inlet passage 56a (inside the laminate 44) circulates through the first flow channels 64 formed in each jig 42.

The activation device 40 includes a second gas line 100. One end of the second gas line 100 is connected to the first outlet passage 58a via a pipe fitting. The other end of the second gas line 100 is connected to a first exhaust line 104 via a first exhaust valve 102. Excess first humidified gas that has flowed through the first passage 64 is discharged from the first exhaust line 104 via the second gas line 100 and the first exhaust valve 102. Alternatively, a recovery device (not shown) may be provided in the first exhaust line 104 to recover the first humidified gas.

The activation device 40 includes a third gas line 110. A nitrogen gas supply unit 112 and an oxidizer gas supply unit 114 are connected to one end of the third gas line 110 via a second three-way valve 116. The nitrogen gas supply unit 112 is, for example, a nitrogen gas tank, as described above. The nitrogen gas is supplied as an inert second gas. In this embodiment, the nitrogen gas supply unit 94 connected to the first gas line 90 and the nitrogen gas supply unit 112 connected to the third gas line 110 are provided separately. However, a single nitrogen gas supply unit may be connected to both the first gas line 90 and the third gas line 110.

The oxidizer gas supply unit 114 is, for example, a compressor that compresses the atmosphere. Alternatively, the oxidizer gas supply unit 114 may be an oxygen gas cylinder. A second humidifier 118 is provided in the third gas line 110. The oxidizer gas supply unit 114 and the second humidifier 118 constitute the second humidifying gas supply unit. The oxidizer gas to which moisture has been added by the second humidifier 118 is the second humidifying gas, acting as the second activating gas.

The other end of the third gas line 110 is connected to the second inlet passage 60a via a pipe fitting. The second wet gas (wet oxidizing gas) flowing from the other end of the third gas line 110 into the second inlet passage 60a (inside the laminate 44) circulates through the second flow channels 72 formed in the individual jigs 42.

The activation device 40 includes a fourth gas line 120. One end of the fourth gas line 120 is connected to the second outlet passage 62a via a pipe fitting. The other end of the fourth gas line 120 is connected to a second exhaust line 124 via a second exhaust valve 122. Excess second humid gas that has flowed through the second passage 72 is discharged from the second exhaust line 124 via the fourth gas line 120 and the second exhaust valve 122. Alternatively, a recovery device (not shown) may be provided in the second exhaust line 124 to recover the second humid gas.

The activation device 40 includes an electrical parameter detection unit 130 and a control unit 134. The electrical parameter detection unit 130 includes, for example, a voltage measuring instrument 136. One voltage measuring instrument 136 is electrically connected to the first electrical terminal 84 of one jig 42 and the second electrical terminal 86 of another jig 42, thereby measuring the voltage of one MEA 10. Hereinafter, this voltage will be conveniently referred to as the "cell voltage." The electrical parameter detection unit 130 may also be a resistance measuring instrument, a current measuring instrument, or an impedance measuring instrument. The electrical parameter detection unit 130 may have all of these measuring instruments.

The activation device 40 further includes a pressure parameter detection unit 140. The pressure parameter detection unit 140 includes an anode differential pressure gauge 142 and a cathode differential pressure gauge 144.

The anode differential pressure gauge 142 detects the differential pressure between the gas pressure in the first gas line 90 and the gas pressure in the second gas line 100. This differential pressure is equal to the differential pressure between the inlet to the anode electrode 16 in the first flow path 64 and the outlet from the anode electrode 16 in the first flow path 64. The cathode differential pressure gauge 144 detects the differential pressure between the gas pressure in the third gas line 110 and the gas pressure in the fourth gas line 120. This differential pressure is equal to the differential pressure between the inlet to the cathode electrode 14 in the second branch path 74 and the outlet from the cathode electrode 14 in the second branch path 74.

The control unit 134 is electrically connected to the heat supply unit 54, the voltage measuring instrument 136, the anode differential pressure gauge 142, and the cathode differential pressure gauge 144. Information regarding the cell voltage measured by the voltage measuring instrument 136 is transmitted to the control unit 134 as an information signal. The control unit 134 also receives information signals regarding the gas differential pressure measured by the anode differential pressure gauge 142 and the cathode differential pressure gauge 144, respectively.

As described later, this embodiment performs power generation aging. Therefore, an external load 154 is electrically connected to the laminate 44 via the first external connection terminal 150 and the second external connection terminal 152.

The activation device 40 according to this embodiment is basically configured as described above. Next, the effects of the activation device 40 according to this embodiment will be explained.

To activate the MEA 10, the operator first alternately stacks the MEA 10 units (before assembly into unit cells) and the jig 42. This forms a laminate 44. The laminate 44 has a first inlet passage 56a, a first outlet passage 58a, a second inlet passage 60a, and a second outlet passage 62a. The first inlet passage 56a, the first outlet passage 58a, the second inlet passage 60a, and the second outlet passage 62a extend along the stacking direction.

The worker connects the first gas line 90 to the first inlet passage 56a and the second gas line 100 to the first outlet passage 58a. Similarly, the worker connects the third gas line 110 to the second inlet passage 60a and the fourth gas line 120 to the second outlet passage 62a.

In this state, the operator issues a command signal to the control unit 134 to "start activation." Based on this command signal, the control unit 134 first replaces the air in the first flow path 64 and the second branch path 74 with moist nitrogen gas.

Upon receiving a command signal, the control unit 134 operates the first three-way valve 96 in a direction that connects the nitrogen gas supply unit 94 to the first gas line 90. Furthermore, the control unit 134 operates the second three-way valve 116 in a direction that connects the nitrogen gas supply unit 112 to the third gas line 110. The control unit 134 also opens the first exhaust valve 102 and the second exhaust valve 122.

The nitrogen gas supplied from the nitrogen gas supply unit 94 passes through the first humidifier 98 to become moist nitrogen gas, and then flows through the first gas line 90. The moist nitrogen gas flows into the first flow path 64 via the first inlet connecting passage 56a (first inlet 56) of the jig 42. The moist nitrogen gas moves from the first inlet 56 to the first distribution path 66, and then from the first distribution path 66 to the first branch path 68. While flowing through the first branch path 68, a portion of the moist nitrogen gas reaches the second electrode catalyst layer 22 via the second gas diffusion layer 24 of the anode electrode 16 of the first MEA 10a. This imparts moisture to the anode electrode 16 and the electrolyte membrane 12.

The excess moist nitrogen gas that has flowed through the first branching channel 68 merges in the first confluence channel 70. The merged moist nitrogen gas then moves from the first confluence channel 70 to the first outlet 58 (first outlet connecting passage 58a). The moist nitrogen gas then flows into the second gas line 100, passes through the first exhaust valve 102, and is discharged from the first exhaust line 104.

The nitrogen gas supplied from the nitrogen gas supply unit 112 passes through the second humidifier 118 to become moist nitrogen gas, and then flows through the third gas line 110. The moist nitrogen gas flows into the second flow path 72 (second branch path 74) via the second inlet connecting passage 60a (second inlet 60) of the jig 42. While flowing through the second branch path 74, a portion of the moist nitrogen gas reaches the first electrode catalyst layer 18 via the first gas diffusion layer 20 of the cathode electrode 14 of the second MEA 10b. This imparts moisture to the cathode electrode 14 and the electrolyte membrane 12.

The excess moist nitrogen gas that has flowed through the second branch passage 74 merges, for example, at the second outlet 62 (second outlet connecting passage 62a). The merged moist nitrogen gas flows into the fourth gas line 120, then passes through the second exhaust valve 122 and is discharged from the second exhaust line 124.

As a result, air is discharged from the first channel 64 and the second channel 72 and replaced with moist nitrogen gas. After a predetermined time has elapsed, the control unit 134 operates the first three-way valve 96 in a direction that connects the hydrogen gas supply unit 92 to the first gas line 90.

The hydrogen gas supplied from the hydrogen gas supply unit 92 passes through the first humidifier 98 to become humidified hydrogen gas (first humidified gas), and then flows into the first flow path 64 via the first inlet communication passage 56a (first inlet 56) of the jig 42. While the first humidified gas flows through the first flow path 64, a portion of it reaches the second electrode catalyst layer 22 via the second gas diffusion layer 24 of the anode electrode 16 of the first MEA 10a. Therefore, the application of moisture to the anode electrode 16 and electrolyte membrane 12 continues. The excess first humidified gas that has flowed through the first flow path 64 moves to the second gas line 100 via the first outlet communication passage 58a, and then passes through the first exhaust valve 102 and is discharged from the first exhaust line 104. This first humidified gas may be recovered by a recovery mechanism (not shown).

Furthermore, the control unit 134 switches the second three-way valve 116, blocking communication between the nitrogen gas supply unit 112 and the third gas line 110, while simultaneously connecting the oxidizer gas supply unit 114 and the third gas line 110. This supplies an oxidizer gas (typically compressed air) containing oxygen. The oxidizer gas passes through the second humidifier 118 to become a humidified oxidizer gas (second humidified gas), and then flows into the second flow path 72 (second branch path 74) via the second inlet communication passage 60a of the jig 42.

A portion of the second humidified gas, while flowing through the second branch passage 74, reaches the first electrode catalyst layer 18 via the first gas diffusion layer 20 of the cathode electrode 14 of the second MEA 10b. Therefore, the application of moisture to the cathode electrode 14 and the electrolyte membrane 12 continues. The excess second humidified gas that has flowed through the second branch passage 74 flows into the fourth gas line 120 via the second outlet communication passage 62a. Subsequently, the second humidified gas passes through the second exhaust valve 122 and is discharged from the second exhaust line 124.

While the second humid gas flows through the second branch 74, a portion of the second humid gas enters the first heat storage unit 80 and the second heat storage unit 82 individually. Since the temperature of the second humid gas is several tens of degrees Celsius to over one hundred degrees Celsius, the first heat storage unit 80 and the second heat storage unit 82 each store heat as this enters. As described above, the heat storage capacity of the second heat storage unit 82 is greater than that of the first heat storage unit 80. The second humid gas that enters the first heat storage unit 80 and the second heat storage unit 82 temporarily remains inside these heat storage units.

In this case, in the second electrode catalyst layer 22 of the anode electrode 16, hydrogen is ionized to produce protons and electrons. The protons conduct through the electrolyte membrane 12 and reach the first electrode catalyst layer 18 of the cathode electrode 14. Electrons reach the first electrode catalyst layer 18 of the cathode electrode 14 via the external load 154. In the first electrode catalyst layer 18, oxygen, protons, and electrons chemically combine to produce water.

The electrochemical reaction described above is an exothermic reaction. That is, MEA 10 becomes heated. When this heat is transferred to the first and second humidified gases, their temperatures rise. At this time, the heat pipe 52 absorbs heat from the first and second humidified gases. In this way, the heat pipe 52 typically cools the first and second humidified gases, respectively.

The control unit 134 constantly receives information signals regarding the cell voltage of the MEA 10. Based on the cell voltage, the control unit 134 determines the concentration overvoltage. Recognizing that the concentration overvoltage has reached a predetermined upper limit based on the increase in humidity within the MEA 10, the control unit 134 determines that "the humidification state of the MEA 10 is at an appropriate upper limit."

The control unit 134 receives input from both the anode differential pressure gauge 142 and the cathode differential pressure gauge 144. As described above, the differential pressure measured by the anode differential pressure gauge 142 is equal to the differential pressure between the inlet to the anode electrode 16 in the first flow path 64 and the outlet from the anode electrode 16 in the first flow path 64. The differential pressure measured by the cathode differential pressure gauge 144 is equal to the differential pressure between the inlet to the cathode electrode 14 in the second branch path 74 and the outlet from the cathode electrode 14 in the second branch path 74. Even if either differential pressure reaches a predetermined upper limit, the control unit 134 determines that "the humidification state of the MEA 10 is at the appropriate upper limit."

Having made the above determination, the control unit 134 increases the temperature of the heat pipe 52. Specifically, the control unit 134 increases the amount of heat transferred from the heat supply unit 54 to the heat pipe 52 by increasing the heat output of the heat supply unit 54.

This control increases the amount of heat supplied from the heat pipe 52 to the first and second humidified gases. Consequently, the effective dew point temperatures of both the first and second humidified gases increase. As a result, condensation becomes less likely in both gases. This gradually reduces the amount of liquid water in the first and second flow paths 64 and 72. As the liquid water volume decreases, the concentration overvoltage, calculated based on the cell voltage, also decreases.

Here, the effective dew point temperature of the first humid gas is the local dew point temperature of the first humid gas at each point in the first flow path 64. Similarly, the effective dew point temperature of the second humid gas is the local dew point temperature of the second humid gas at each point in the second flow path 72. The effective dew point temperatures of the first and second humid gases are determined by the amount of heat supplied from the heat pipe 52 to each of the first and second humid gases.

If the liquid water levels in the first channel 64 and the second branch channel 74 decrease excessively, there is a concern that the electrolyte membrane 12 may dry out. Therefore, when the concentration overvoltage reaches a predetermined lower limit, the control unit 134 determines that "the humidification state of the MEA 10 is at the appropriate lower limit." The control unit 134 also makes the same determination when the differential pressure between the first gas line 90 and the second gas line 100 reaches a predetermined lower limit.

Having made the above determination, the control unit 134 lowers the temperature of the heat pipe 52. Specifically, the control unit 134 reduces the amount of heat transferred from the heat supply unit 54 to the heat pipe 52 by reducing the amount of heat generated by the heat supply unit 54.

This control reduces the amount of heat supplied from the heat pipe 52 to the first and second humidified gases. Consequently, the effective dew point temperatures of both the first and second humidified gases decrease. As a result, condensation becomes more likely in both gases. This causes a gradual increase in the liquid water content in the first and second flow paths 64 and 72. As the liquid water content increases, the concentration overvoltage, calculated based on the cell voltage, increases. Furthermore, the differential pressure between the first gas line 90 and the second gas line 100 increases.

The heat pipe 52 has a high response speed to heat supply and cessation. Therefore, when heat is supplied to the heat pipe 52 from the heat supply unit 54, the temperature of the first humidified gas in the first channel 64 and the temperature of the second humidified gas in the second channel 72 rise rapidly. Conversely, when the supply of heat from the heat supply unit 54 to the heat pipe 52 stops, the temperature of the first humidified gas in the first channel 64 and the temperature of the second humidified gas in the second channel 72 fall rapidly.

As described above, the temperatures of the first and second humidified gases are rapidly adjusted. That is, the temperatures of the first and second humidified gases can be maintained at approximately constant levels. Therefore, the liquid water volume in each of the first and second flow paths 64 and 72 can be maintained at appropriate levels, thus preventing flooding. Thus, according to this embodiment, when activating multiple MEAs 10 simultaneously, flooding in the first and second flow paths 64 and 72 of the jig 42 can be prevented.

As a result, a sufficient amount of the first humidifying gas reaches the second electrode catalyst layer 22 of the anode electrode 16, and a sufficient amount of the second humidifying gas reaches the first electrode catalyst layer 18 of the cathode electrode 14. This allows the MEA 10 to be sufficiently activated.

In addition, a first heat storage section 80 and a second heat storage section 82 are formed in the middle of the second branching passage 74. Heat is stored in the first heat storage section 80 and the second heat storage section 82 as the second humid gas enters. Therefore, heat is transferred from the first heat storage section 80 and the second heat storage section 82 to the second humid gas flowing through the second branching passage 74. Since the heat storage capacity of the second heat storage section 82 is larger than that of the first heat storage section 80, a larger amount of heat is transferred to the second humid gas as it approaches the second outlet 62.

Therefore, in this embodiment, a large amount of heat is supplied to the second humid gas as it approaches the second outlet 62. Consequently, even if the amount of heat supplied from the heat pipe 52 rapidly decreases in the second flow path 72, a decrease in the effective dew point temperature is avoided, particularly near the second outlet 62. Therefore, flooding in the second flow path 72 is suppressed. In other words, flooding can be easily prevented even when multiple MEAs 10 are activated simultaneously.

Furthermore, in this embodiment, the heat storage capacity of the heat storage section is increased as it approaches the second outlet 62. Therefore, in the second flow path 72, the dew point temperature increases from the second inlet 60 towards the second outlet 62. That is, in the second flow path 72, a positive gradient is formed in the effective dew point temperature as the second humid gas flows from upstream to downstream. Therefore, even when the effective dew point temperature of the second humid gas decreases in the second flow path 72, the formation of condensed water (liquid water) is suppressed throughout the entire second flow path 72.

Furthermore, in this embodiment, the effective dew point temperature is highest near the second outlet 62 in the second flow path 72. Therefore, condensation is less likely to form at the second outlet 62. This prevents the second outlet 62 from being blocked by condensation. Consequently, any condensation generated along the second flow path 72 can be quickly discharged from the second outlet 62.

After the activation of MEA10 is completed as described above, the control unit 134 controls the first three-way valve 96 to block the connection between the hydrogen gas supply unit 92 and the first gas line 90, and to open the connection between the nitrogen gas supply unit 94 and the first gas line 90. Furthermore, the control unit 134 controls the second three-way valve 116 to block the connection between the third gas line 110 and the oxidizer gas supply unit 114, and to open the connection between the third gas line 110 and the nitrogen gas supply unit 112.

In this state, nitrogen gas is supplied from the nitrogen gas supply unit 94 to the first channel 64, and nitrogen gas is supplied from the nitrogen gas supply unit 112 to the second channel 72. The nitrogen gas becomes moist nitrogen gas and is supplied to the anode electrode 16 and the cathode electrode 14. The moist nitrogen gas is discharged from the first exhaust valve 102 and the second exhaust valve 122, respectively, via the second gas line 100 and the fourth gas line 120. As a result, the first channel 64 and the second channel 72 are replaced with moist nitrogen gas.

In this embodiment, an example is shown in which the heat pipe 52 extends in a direction perpendicular to the first branch 68 and the second branch 74. However, the direction in which the heat pipe 52 extends is not particularly limited. For example, as shown in Figures 6 and 7, the heat pipe 52 may extend parallel to the first branch 68 and the second branch 74. Note that in Figures 6 and 7, the same reference numerals are used for components that are the same as those shown in Figures 1 to 5.

In this embodiment, the heat supply unit 54 can be positioned, for example, between the first inlet 56 and the second outlet 62. In this case, at least a portion (preferably all) of the heat supply unit 54 fits within the jig 42. Therefore, the activation device 40 can be miniaturized.

As described above, this embodiment is an activation device (40) for activating an electrolyte membrane/electrode structure (10) in which an electrolyte membrane (12) is sandwiched between an anode electrode (16) and a cathode electrode (14) constituting a fuel cell, and comprises a plurality of jigs (42) stacked with the electrolyte membrane/electrode structure sandwiched between them, a heat pipe (52) provided on each of the plurality of jigs, a heat supply unit (54) that applies heat to the heat pipe, a control unit (134) that controls the heat applied from the heat supply unit to the heat pipe, a first activation gas supply source that supplies a first activation gas, and a second activation gas supply source that supplies a second activation gas, wherein each of the plurality of jigs has a first surface (46) facing the anode electrode, a second surface (48) facing the cathode electrode, and a first inlet extending along the stacking direction of the plurality of jigs and into which the first activation gas flows. The present invention discloses an activation device comprising: (56); a first flow path (64) extending along the first surface and communicating with the first inlet; a first outlet (58) extending along the stacking direction and through which the first activated gas that has flowed through the first flow path flows out; a second inlet (60) extending along the stacking direction and through which the second activated gas flows in; a second flow path (72) extending along the second surface and communicating with the second inlet; and a second outlet (62) extending along the stacking direction and through which the second activated gas that has flowed through the second flow path flows out. The first and second flow paths extend in directions parallel to or perpendicular to the heat pipe, and when viewing the first or second surface of each of the plurality of fixtures, the first inlet, first outlet, second inlet, and second outlet are spaced apart from each other in the direction of extension of the heat pipe and in directions perpendicular to the direction of extension.

Heat pipes exhibit a high response speed to heat input or output. Therefore, by exchanging heat between the heat pipe and the first and second activated gases, the temperatures of the first and second activated gases can be rapidly adjusted. In other words, the temperatures of the first and second activated gases are adjusted to a predetermined range.

This adjusts the effective dew point temperatures of the first and second activating gases to an appropriate temperature range. As a result, the liquid water content in the first and second channels of the jig is maintained within an appropriate range. Therefore, it is possible to appropriately apply moisture to multiple electrolyte membrane and electrode structures while avoiding flooding in the first and second channels. In this way, multiple electrolyte membrane and electrode structures can be activated simultaneously.

This embodiment discloses an activation device in which the first flow path has a plurality of first branch paths (68), the plurality of first branch paths branching from the first inlet or first distribution path (66) and converging at the first gathering path (70) or the first outlet, and the second flow path has a plurality of second branch paths (74), the plurality of second branch paths branching from the second inlet or second distribution path (76) and converging at the second gathering path (78) or the second outlet.

The first and second branching pathways allow the first and second activating gases to reach a wide area of the electrolyte membrane and electrode structure. That is, the electrolyte membrane and electrode structure can be activated over a wide area. Furthermore, by combining the first branching pathways, the first inlet where the first activating gas flows in is consolidated into a single location. The first outlet where the first activating gas flows out is also consolidated into a single location. The same applies to the second branching pathway. Therefore, the size of the jig can be reduced.

Furthermore, when multiple jigs are stacked, aligning the positions of the first entrance, first exit, second entrance, and second exit makes it easy to form the first entrance passage, first exit passage, second entrance passage, and second exit passage extending in the direction of jig stacking.

This embodiment discloses an activation device having a heat storage section (80, 82) provided in at least one of the first or second flow channels.

Heat pipes exhibit a high response speed to heat supply and/or cessation of heat supply. Therefore, when the temperature of the activated gas flowing through the gas channel of an activation device is controlled by a heat pipe, it is presumed that the local temperature (effective dew point temperature) of the activated gas becomes nearly uniform. In this case, when the amount of heat supplied to the activated gas from the heat pipe rapidly decreases, the effective dew point temperature of the activated gas within the gas channel may drop simultaneously, potentially causing condensation throughout the entire gas channel. This phenomenon is expected to cause flooding, despite the high response speed of the heat pipe to heat inflow and outflow. In particular, fuel cell stacks installed in large vehicles such as trucks tend to have larger MEAs. When activating such MEAs, the flow path length of the gas channel in the activation device becomes relatively long. In gas channels with long flow paths, the amount of condensation generated is large, raising concerns about the likelihood of flooding.

In contrast, in a configuration with a heat storage unit, heat from the heat storage unit is transferred to the activated gas flowing through the gas channel. This heat transfer increases the effective dew point temperature of the activated gas. As a result, condensation of water vapor within the gas channel is further suppressed. Therefore, preventing flooding becomes even easier.

This embodiment discloses an activation device in which the heat storage section is one or more recesses that are recessed starting from the first or second flow path and spaced apart from the first or second flow path.

In this case, the activated gas enters the recess. Since the activated gas is tens of degrees Celsius to over a hundred degrees Celsius, the heat storage section stores heat. Thus, this configuration makes it easy to construct the heat storage section.

This embodiment discloses an activation device in which the heat storage section consists of two or more recesses that are recessed from the first or second flow path, with the heat storage capacities of the two or more recesses being different from each other, and the two or more recesses are arranged in the first flow path from the first inlet to the first outlet in order from the recess with the smallest heat storage capacity to the recess with the largest heat storage capacity, or in the second flow path from the second inlet to the second outlet in order from the recess with the smallest heat storage capacity to the recess with the largest heat storage capacity.

In this case, the effective dew point temperature increases as you move from the upstream to the downstream of the first or second flow path (gas flow path). That is, a positive temperature gradient is formed in the effective dew point temperature. Therefore, condensation from the activated gas becomes less likely as you move from the inlet to the outlet of the gas flow path. For this reason, simultaneous condensation throughout the entire gas flow path is avoided. Furthermore, since the effective dew point temperature can be increased near the outlet of the gas flow path, condensation is suppressed at the outlet. Therefore, blockage of the gas flow path outlet by condensation is avoided. For this reason, even if condensation is generated from the activated gas midway through the gas flow path, the condensation can be quickly discharged from the outlet.

In particular, during power generation aging, water is generated at the cathode electrode as activation progresses. Therefore, flooding is likely to occur near the second outlet of the second channel facing the cathode electrode. However, in the above configuration, it is possible to supply a large amount of heat from the heat storage unit located near the first or second outlet to the activated gas that has flowed through the first or second channel and reached the vicinity of the first or second outlet. Therefore, a decrease in the effective dew point temperature of the activated gas near the outlet can be avoided. This further suppresses the occurrence of flooding.

This embodiment discloses an activation device in which the first and second flow paths extend so as to intersect with the heat pipe, and the heat supply unit is positioned at the end of the heat pipe in the direction of extension.

This embodiment discloses an activation device in which the first and second flow paths and the heat pipe extend parallel to each other, and the heat supply unit is positioned between two of the first inlet, first outlet, second inlet, and second outlet.

In either case, it is possible to reduce the protrusion of the heat supply section from the jig. Therefore, the jig and activation device can be miniaturized.

Typically, the first inlet and first outlet are formed at diagonal positions to each other. Similarly, the second inlet and second outlet are formed at diagonal positions to each other. That is, this embodiment discloses an activation device in which the first inlet and first outlet are diagonally positioned, and the second inlet and second outlet are also diagonally positioned.

In this case, it is easy to evenly contact the entire anode electrode with the first activating gas. Similarly, it is easy to evenly contact the entire cathode electrode with the second activating gas. Therefore, the MEA can be activated almost uniformly throughout.

Furthermore, the present invention is not limited to the disclosures described above, and various configurations can be adopted without departing from the spirit of the invention.

10, 10a, 10b...Electrolyte membrane/electrode structure 12...Electrolyte membrane 14...Cathode electrode 16...Anode electrode 40...Activation device 42...Jig 44...Laminate 46...First surface 48...Second surface 52...Heat pipe 54...Heat supply section 56...First inlet 56a...First inlet connecting passage 58...First outlet 58a...First outlet connecting passage 60...Second inlet 60a...Second inlet connecting passage 62...Second outlet 62a...Second outlet connecting passage 64...First flow path 66...First distribution path 68...First branch path 70...First assembly path 72...Second flow path 74...Second branch path 76...Second distribution path 78...Second assembly path 80...First heat storage section 82...Second heat storage section 90...First gas line 92...Hydrogen gas supply section 98...First humidifier 100...Second gas line 110...Third gas line 114...Oxidizer gas supply unit 118...Second humidifier 120...Fourth gas line 130...Electrical parameter detection unit 134...Control unit 136...Voltage measuring instrument 140...Pressure parameter detection unit 142...Anode differential pressure gauge 144...Cathode differential pressure gauge 154...External load

Claims (6)

In an activation device for activating an electrolyte membrane/electrode structure in which an electrolyte membrane is sandwiched between the anode electrode and cathode electrode constituting a fuel cell,
Multiple jigs are stacked with the electrolyte membrane/electrode structure sandwiched between them,
A heat pipe is provided on each of the aforementioned multiple jigs,
A heat supply unit that applies heat to the heat pipe,
A control unit that controls the heat supplied from the heat supply unit to the heat pipe,
A first activated gas supply source that supplies the first activated gas,
A second activated gas supply source that supplies the second activated gas,
Equipped with,
Each of the aforementioned multiple jigs has a first surface facing the anode electrode,
The second surface facing the cathode electrode,
A first inlet extending along the stacking direction of the plurality of jigs and into which the first activated gas flows,
A first channel extending along the first surface and communicating with the first inlet,
A first outlet extending along the stacking direction and through which the first activated gas that has flowed through the first channel flows out,
A second inlet extending along the stacking direction and into which the second activated gas flows,
A second flow path extending along the second surface and communicating with the second inlet,
A second outlet extending along the stacking direction and through which the second activated gas that has flowed through the second channel flows out,
It has,
The first and second flow paths extend in directions parallel to or intersecting the heat pipe.
When the first or second surface of each of the plurality of jigs is viewed, the first inlet, the first outlet, the second inlet, and the second outlet are spaced apart from each other in the direction in which the heat pipe extends, and are also spaced apart from each other in a direction perpendicular to the direction in which the heat pipe extends.
The activation device further comprises a heat storage unit provided in at least one of the first or second flow channels.
The heat storage section is one or more recesses that are recessed starting from the first flow path or the second flow path and spaced apart from the first flow path or the second flow path , in an activation device. In an activation device for activating an electrolyte membrane/electrode structure in which an electrolyte membrane is sandwiched between the anode electrode and cathode electrode constituting a fuel cell,
Multiple jigs are stacked with the electrolyte membrane/electrode structure sandwiched between them,
A heat pipe is provided on each of the aforementioned multiple jigs,
A heat supply unit that applies heat to the heat pipe,
A control unit that controls the heat supplied from the heat supply unit to the heat pipe,
A first activated gas supply source that supplies the first activated gas,
A second activated gas supply source that supplies the second activated gas,
Equipped with,
Each of the aforementioned multiple jigs has a first surface facing the anode electrode,
The second surface facing the cathode electrode,
A first inlet extending along the stacking direction of the plurality of jigs and into which the first activated gas flows,
A first channel extending along the first surface and communicating with the first inlet,
A first outlet extending along the stacking direction and through which the first activated gas that has flowed through the first channel flows out,
A second inlet extending along the stacking direction and into which the second activated gas flows,
A second flow path extending along the second surface and communicating with the second inlet,
A second outlet extending along the stacking direction and through which the second activated gas that has flowed through the second channel flows out,
It has,
The first and second flow paths extend in directions parallel to or intersecting the heat pipe.
When the first or second surface of each of the plurality of jigs is viewed, the first inlet, the first outlet, the second inlet, and the second outlet are spaced apart from each other in the direction in which the heat pipe extends, and are also spaced apart from each other in a direction perpendicular to the direction in which the heat pipe extends.
The activation device further comprises a heat storage unit provided in at least one of the first or second flow channels.
The heat storage section is a set of two or more recesses that are recessed starting from the first or second flow path and spaced apart from the first or second flow path.
The heat storage capacities of the two or more recesses differ from each other.
An activation device in which the two or more recesses are arranged in the first flow path from the first inlet to the first outlet in order from recesses with small heat storage capacity to recesses with large heat storage capacity, or in the second flow path from the second inlet to the second outlet in order from recesses with small heat storage capacity to recesses with large heat storage capacity. In an activation device for activating an electrolyte membrane/electrode structure in which an electrolyte membrane is sandwiched between the anode electrode and cathode electrode constituting a fuel cell,
Multiple jigs are stacked with the electrolyte membrane/electrode structure sandwiched between them,
A heat pipe is provided on each of the aforementioned multiple jigs,
A heat supply unit that applies heat to the heat pipe,
A control unit that controls the heat supplied from the heat supply unit to the heat pipe,
A first activated gas supply source that supplies the first activated gas,
A second activated gas supply source that supplies the second activated gas,
Equipped with,
Each of the aforementioned multiple jigs has a first surface facing the anode electrode,
The second surface facing the cathode electrode,
A first inlet extending along the stacking direction of the plurality of jigs and into which the first activated gas flows,
A first channel extending along the first surface and communicating with the first inlet,
A first outlet extending along the stacking direction and through which the first activated gas that has flowed through the first channel flows out,
A second inlet extending along the stacking direction and into which the second activated gas flows,
A second flow path extending along the second surface and communicating with the second inlet,
A second outlet extending along the stacking direction and through which the second activated gas that has flowed through the second channel flows out,
It has,
The first and second flow paths extend in directions parallel to or intersecting the heat pipe.
When the first or second surface of each of the plurality of jigs is viewed, the first inlet, the first outlet, the second inlet, and the second outlet are spaced apart from each other in the direction in which the heat pipe extends, and are also spaced apart from each other in a direction perpendicular to the direction in which the heat pipe extends.
An activation device in which the first flow path and the second flow path and the heat pipe extend in parallel, and the heat supply unit is positioned between two of the first inlet, first outlet, second inlet, and second outlet. An activation device according to any one of claims 1 to 3 , wherein the first flow path has a plurality of first branch paths, the plurality of first branch paths branch off from the first inlet or first distribution path and converge at the first gathering path or the first outlet, and the second flow path has a plurality of second branch paths, the plurality of second branch paths branch off from the second inlet or second distribution path and converge at the second gathering path or the second outlet. An activation device according to any one of claims 1 to 3 , wherein the first flow path and the second flow path extend so as to intersect with the heat pipe, and the heat supply unit is located at the end of the heat pipe in the direction of extension. An activation device according to any one of claims 1 to 3 , wherein the first inlet and the first outlet are in a diagonal positional relationship, and the second inlet and the second outlet are in a diagonal positional relationship.