JP2010153266A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent electrolyte of an air guide-in part from drying, in a type of a fuel cell equipped with a hydrogen gas flow channel of a dead-end type. <P>SOLUTION: The fuel cell is provided with an air flow channel 50 for circulating air from the first side to the second side, at the air-electrode side of the fuel cell equipped with the first side and the second side opposed to each other, as well as, a dead-end type hydrogen gas flow channel 30 at a fuel electrode side. The hydrogen gas flow channel is provided with a first hydrogen gas flow channel 31, with the second side as the hydrogen gas guide-in port; a second hydrogen gas flow channel 32 parallel with the first hydrogen gas flow channel 31; and a first bent part 31c for connecting a first side end part of the first hydrogen gas flow channel 31 and a first side-end part of the second hydrogen gas flow channel 32. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cell.

  Small size and low cost are required for future fuel cell commercialization. For this reason, the operating conditions are “high temperature / no humidification” for simplification of the cooling / humidification system, and “air normal pressure / low flow rate” for eliminating the pressurizing pump, small fan / low auxiliary power, and circulation. It is predicted that "hydrogen pressurization dead end and no circulation" will occur due to pump elimination.

  When the fuel cell is set to “high temperature / no humidification”, proton conduction decreases due to drying of the electrolyte, and power generation characteristics deteriorate. As a countermeasure, a counterflow that reverses the direction of the flow of hydrogen gas and air flowing to the anode or cathode is widely known. In this counterflow, the gas introduction part of each electrode becomes the flow path end of the counter electrode, so that the inside of the MEA can be appropriately wetted by the mutual movement of water via the electrolyte, so that drying of the air introduction part can be suppressed.

  However, in particular, in the combination of “high temperature / no humidification” and “hydrogen pressurization dead end / no circulation”, the effect of wetting in the MEA caused by the counter flow is reduced. This is because in the hydrogen dead end system, the flow of hydrogen gas serving as a water vapor carrier stops at the end of the flow path. For this reason, in the hydrogen dead end system, with the inflow of non-humidified air from the air introduction part facing the end of the flow path, the electrolyte in the air introduction part dries and power generation characteristics deteriorate. In addition, a vicious cycle occurs in which drying proceeds on the hydrogen introduction side due to a decrease in the amount of hydrogen consumption accompanying a decrease in power generation characteristics at the drying site. In such a state, only a part of the MEA contributes to power generation, and the original power generation characteristics cannot be obtained.

  The present invention has been made to solve the above-described conventional problems, and is a type of a fuel cell having a dead-end type hydrogen gas flow path on the fuel electrode side, wherein the electrolyte in the air introduction part is dried. It aims at providing the fuel cell which prevents.

The fuel cell of the first aspect is
The fuel cell having an opposing first side and second side includes an air flow path for circulating air from the first side to the second side on the air electrode side of the fuel cell, and dead on the fuel electrode side. A fuel cell comprising an end-type hydrogen gas flow path,
The hydrogen gas flow path includes a first hydrogen gas flow path having the second side side as a hydrogen gas inlet, a second hydrogen gas flow path parallel to the first hydrogen gas flow path, A first bent portion connecting the first side-side end of the first hydrogen gas flow path and the first side-side end of the second hydrogen gas flow path. is there.
According to this fuel cell, the hydrogen gas flows to the first hydrogen gas flow channel, the first bent portion, and the second hydrogen gas flow channel, and the hydrogen gas flow channel is a dead end type. The hydrogen gas flow disappears at the end of the hydrogen gas flow path.
On the other hand, in the conventional straight hydrogen gas flow path, the flow of hydrogen gas stops at a portion facing the introduction side of the air flow path, whereas according to the fuel cell of the first aspect, the dead end type In other words, the amount of hydrogen gas with respect to the introduction facing portion of the air flow path is the first bent portion. , Depending on the amount flowing into the second hydrogen gas flow path. Thereby, the flow of hydrogen gas with respect to the air introduction facing portion increases and functions as a water vapor carrier gas, and drying of the air flow passage introduction portion can be suppressed. Therefore, it is possible to prevent a decrease in power generation performance due to drying of the introduction portion of the air flow path.
Further, the shape of the first bent portion is not particularly limited as long as it is bent, but a U shape is preferable in consideration of pressure loss and increase in the length in the width direction.

In the fuel cell according to the second aspect, it is preferable that an end of the second hydrogen gas flow path is adjacent to the hydrogen gas inlet on the second side.
As a result, the end of the second hydrogen gas flow channel is adjacent to the hydrogen gas inlet, so the length of the second hydrogen gas flow channel is substantially the same as the first hydrogen gas flow channel.
Therefore, since the amount of hydrogen gas with respect to the air introduction facing portion increases with the length of the second hydrogen gas flow channel, drying of the air flow channel introduction portion can be further suppressed as compared with the fuel cell of the first aspect. .
In addition, since flows in opposite directions are respectively generated in the first and second hydrogen gas flow paths, the effect of facing soot can be expected in the fuel electrode.
In addition, the hydrogen gas flow path has, for example, a substantially U shape by the first hydrogen gas flow path, the first bent portion, and the second hydrogen gas flow path. Since the projected area formed by the hydrogen gas flow path can be made narrower than when the end of the second hydrogen gas flow path is separated from the hydrogen gas inlet on the second side, it is possible to make it compact And the installation area can be reduced. If the installation area is the same, a large number of such hydrogen gas flow paths can be installed, so that drying of the introduction part of the air flow path can be further suppressed.

In the fuel cell of the third aspect, the hydrogen gas flow path includes a third hydrogen gas flow path parallel to the second hydrogen gas flow path, and the second side of the second hydrogen gas flow path. A second bent portion connecting an end portion and the second side-side end portion of the third hydrogen gas flow path, and the terminal end of the third hydrogen gas flow path is the first side It is preferable that it is adjacent to the first bent portion on the side.
Thereby, hydrogen gas flows from the hydrogen gas inlet and flows through the first hydrogen gas flow path, the first bent portion, the second hydrogen gas flow path, the second bent portion, and the third hydrogen gas flow path. The flow of hydrogen gas disappears at the end of the third hydrogen gas flow path. Therefore, in the fuel cell of the third aspect, the amount of hydrogen gas with respect to the air introduction facing portion has the second bent portion and the third hydrogen gas flow in addition to the first bent portion and the second hydrogen gas flow path. Since the flow rate increases by the amount flowing to the road, the flow rate flowing through the second bent portion and the third hydrogen gas flow path can be increased as compared with the fuel cell of the second aspect. It can be suppressed more.
In the fuel cell of the third aspect, since the terminal end of the third hydrogen gas channel is adjacent to the first bent portion, the length of the third hydrogen gas channel is the first hydrogen gas flow. Almost the same as the road. Since the amount of hydrogen gas with respect to the air introduction facing portion increases with the length of the hydrogen gas passage, wetting of the introduction portion of the air passage can be increased.

  Further, in the fuel cell of the third aspect, since the terminal end of the third hydrogen gas channel is adjacent to the first bent portion, there is a flow in opposite directions in the first and third hydrogen gas channels. Since this occurs, the effect of the opposing soot can be expected in the fuel electrode. In addition, the hydrogen gas flow path is substantially N-shaped by overlapping the central gas flow path of, for example, a U shape and an inverted U shape by the first to third hydrogen gas flow paths. Since the projected area formed by the first to third hydrogen gas passages can be narrowed, it is possible to reduce the size and reduce the installation area of the hydrogen gas passages. If the installation area is the same, a large number of such hydrogen gas flow paths can be installed, so that drying of the introduction part of the air flow path can be further suppressed.

In the fuel cell according to the fourth aspect, it is preferable that the first hydrogen gas channel is formed narrower than the second hydrogen gas channel.
As a result, the amount of hydrogen gas flowing through the air introduction facing portion increases as the width of the second hydrogen gas flow path increases, but has little relation to the width of the first hydrogen gas flow path. Therefore, the width of the second hydrogen gas flow path is wider than the width of the first hydrogen gas flow path compared to the case where the widths of the first hydrogen gas flow path and the second hydrogen gas flow path are the same. As a result, the flow rate of hydrogen gas flowing in the opposite part of the air introduction part further increases. Therefore, the fuel cell of the fourth aspect can increase the amount of hydrogen gas flowing to the air-introducing facing portion even in the same area of the hydrogen gas flow path, so that more water vapor can be moved to the air-introducing facing portion. It is possible to prevent drying of the introduction portion of the air flow path.

Example 1
An embodiment of the present invention will be described with reference to FIGS. 1 is a cross-sectional view of a single cell in a fuel cell stack, FIG. 2 is a detailed view of a hydrogen gas flow path section shown in FIG. 1, and FIG. 3 shows a relationship between the hydrogen gas flow path and the air flow path shown in FIG. It is a schematic diagram.
In the fuel cell, a plurality of unit units U are connected. As shown in FIG. 1, each unit unit U has a cathode side catalyst layer 12 a and an anode side catalyst layer 12 b laminated on both surfaces of a polymer electrolyte membrane 11. The outer side is sandwiched between the cathode side diffusion layer 13 and the anode side diffusion layer 14 to constitute the MEA 10. Furthermore, it is press-contacted by the ribs 16a and 17a of the separators 16 and 17 from both sides of the MEA 10, and thereby a dead end type in which hydrogen gas flows between the separators 16 and 17 and the cathode side diffusion layer 13 and the anode side diffusion layer 14. The hydrogen gas flow path portion 20 and the air flow path 50 through which air flows are formed.

  As shown in FIGS. 2 and 3, the hydrogen gas flow path unit 20 has a large number of hydrogen gas flow paths 30 facing the MEA 10, and the N-shaped hydrogen gas flow path 30 has two U shapes. The parts are communicated with each other so as to be substantially N-shaped. The air flow path 50 corresponds to the horizontal first side (lower side) 10a and the horizontal second side (upper side) 10c of the MEA 10 facing each other, and also on the air electrode side, the first side 10a and the second side The side 10c is formed so as to circulate air from the first side 10a side to the second side 10c side.

The N-shaped hydrogen gas flow channel 30 includes a first hydrogen gas flow channel 31, a second hydrogen gas flow channel 32, and a third hydrogen gas flow channel that are provided at equal intervals and have the same width and substantially the same length. 33, the end portion of the first hydrogen gas flow path 31 and the start end portion of the second gas flow path 32 are communicated by the first bent portion 31c, and the second hydrogen gas flow path 32 The end portion and the start end portion of the third gas flow path 32 are communicated with each other by the second bent portion 32c, and the first bent portion 31c is connected to the introduction portion of the air flow path 50 and the third hydrogen via the MEA 10. It faces the discharge part of the gas flow path 33.
Further, the N-shaped hydrogen gas flow channel 30 has a second bent portion 32c facing the hydrogen introduction portion of the first hydrogen gas flow channel 31, and the air flow channel 50 via the hydrogen introduction portion and the MEA 10. Opposite the discharge section.

  The N-shaped hydrogen gas flow path 30 has the second side 10c side as a hydrogen gas inlet 20a, a first hydrogen gas flow path 31 parallel to the air flow path 50, and a first hydrogen gas. A second hydrogen gas channel 32 parallel to the channel 31, a first side edge of the first hydrogen gas channel 31, and a first side edge of the second hydrogen gas channel 22 U-shaped first bent portion 31c is connected.

The N-shaped hydrogen gas flow channel 30 is adjacent to the end of the second hydrogen gas flow channel 32 facing the hydrogen gas inlet 30a on the second side.
Further, the N-shaped hydrogen gas flow channel 30 includes a third hydrogen gas flow channel 33 parallel to the second hydrogen gas flow channel 32 and a second side end of the second hydrogen gas flow channel 32 and the second hydrogen gas flow channel 32. 3 has a U-shaped second bent portion 32c that connects the second side end of the third hydrogen gas flow path 33, and the end of the third hydrogen gas flow path 33 is located on the first side side. It is adjacent to the first bent portion 31c.
Since the N-shaped hydrogen gas flow path 30 includes the first bent portion 31c and the second bent portion 32c, the number of turns serving as the number of turns is formed twice.

<Calculation of the hydrogen gas amount Qd at the end of the hydrogen gas flow path unit 20>
As shown in FIG. 4, when the hydrogen gas flow path 30 is turned n times (turned back) in the hydrogen dead-end system, a portion of the N-shaped hydrogen gas flow path 30 facing the introduction portion of the air flow path 50 ( The amount of hydrogen gas in the air flow channel facing the introduction of the air flow channel flows in a portion corresponding to the terminal minute region a × W, and under the assumption that there is no power generation distribution of the MEA 10, hydrogen within the dotted frame shown in FIG. This corresponds to the amount of hydrogen consumed in the area multiplied by the number of flow paths forming the gas flow path 30.

ここに、Ｄ：ＭＥＡ１０の縦寸法、Ｗ:ＭＥＡ１０の横寸法、ａ：末端微小領域の寸法
ｎ：水素ガス流路のターン数、ｎ_ｓ：水素ガス流路の本数（組数）
Ｐｒ：リブ幅、Ｐｄ：水素ガス流路の幅
Ｃ_Ｈ２：電極面積Ｄ×Ｗにおける水素消費量（ファラデー則）
また、水素ガス流路３０の本数ｎ_ｓは下式で示せるため

水素ガス流路部２０の末端部における水素ガス量Ｑ_ｄは下式となる。

空気流路５０の導入対向部の水素ガス量Ｑ_ｄは数式３によれば、水素ガス流路３０の長さ方向のＭＥＡ１０の形状に基づく寸法Ｄと、Ｎ形状の水素ガス流路３０の末端部の指標とするべく設けた任意寸法である末端微小領域の長さａ、及び水素ガス流路３０の屈曲部３１ｃ,３２cの数となるターン数ｎによって決定される。 That is, assuming that the total hydrogen consumption of the MEA 10 is C _H2 , the hydrogen gas amount Q _{d at} the introduction facing portion of the air flow path 50 is expressed by the following formula according to the ratio with the total area D × W of the MEA 10.

Here, D: vertical dimension of MEA 10, W: horizontal dimension of MEA 10, a: dimension of terminal minute region n: number of turns of hydrogen gas flow path, n _s : number of hydrogen gas flow paths (number of sets)
Pr: rib width, Pd: width of hydrogen gas flow path C _H2 : hydrogen consumption in electrode area D × W (Faraday rule)
Further, the number n _s of the hydrogen gas channel 30 for can show the following formula

Hydrogen gas amount Q _d at the distal portion of the hydrogen gas channel portion 20 becomes the following expression.

According to Equation 3, the hydrogen gas amount Q _{d at} the introduction facing portion of the air flow channel 50 is the dimension D based on the shape of the MEA 10 in the length direction of the hydrogen gas flow channel 30 and the end of the N-shaped hydrogen gas flow channel 30. It is determined by the length a of the terminal minute region, which is an arbitrary dimension provided as an index of the portion, and the number of turns n that is the number of the bent portions 31c, 32c of the hydrogen gas flow path 30.

即ち、数式４によれば、水素ガス流路部２０のターン数ｎが大きいほど末端微小領域に流れる水素ガスが多く、対向流の効果が増大することになる。
末端微小領域ａ＝０．５ｃｍとおいたとき、燃料電池スタックとして現実的なＭＥＡ１０のＤ寸法５〜２０ｃｍを本式に代入すると、図６に示す結果が得られる。 <Hydrogen gas amount ratio Q _d / C _H2 to total MEA hydrogen consumption>
Hydrogen gas amount Q _d of the air introduction opposing portions hydrogen dead end system, since not more than the total hydrogen consumption of MEA 10, by modifying the Equation 3, the hydrogen of the facing portion of the air introduced to hydrogen consumption of the whole MEA The following formula is obtained by arranging the relationship of the gas amount ratio Q _d / _{CH 2} .

That is, according to Equation 4, the larger the number n of turns of the hydrogen gas flow path section 20 is, the more hydrogen gas flows in the terminal minute region, and the effect of counterflow increases.
When the terminal minute region a = 0.5 cm is set, the result shown in FIG. 6 is obtained by substituting 5 to 20 cm for the D dimension of the MEA 10 that is practical as a fuel cell stack.

数式５によれば、物理的には、ターン数プラス１が水素ガス流路部２０の全体本数に相当し、ターン数が第１の水素ガス流路３１を除く水素ガス流路の本数となる。 According to FIG. 6, the amount of hydrogen gas at the air introduction facing portion hardly depends on the D dimension of the MEA 10, and changes depending on the number of turns (number of bent portions) of the N-shaped hydrogen gas flow path 30. This is because the amount of hydrogen gas flowing into the introduction facing portion of the air flow path 50 can be determined simply by the parameter of the number of turns regardless of the flow path shape such as the groove width, groove pitch and length of the hydrogen gas flow path 30. Means.
This can also be understood from the fact that the numerator of Formula 4 is nD >> a, and thus the following formula.

According to Equation 5, physically, the number of turns plus 1 corresponds to the total number of the hydrogen gas passages 20, and the number of turns is the number of hydrogen gas passages excluding the first hydrogen gas passage 31. .

Therefore, the counter flow can be increased by increasing the number of turns of the hydrogen gas flow path 30 and increasing the amount of hydrogen gas flowing in the terminal minute region. Furthermore, according to FIG. 6, an increase in the amount of hydrogen gas Q _d due to the turn number of the introduction opposite part of the air passage 50 is sufficiently obtained even below 5 times.

  On the other hand, when the number of turns of the hydrogen gas flow path 30 increases, the pressure loss of the hydrogen gas flow path 30 increases, or the condensed water generated when the cell temperature decreases mainly during stoppage of the hydrogen gas flow path 30 There is a risk of clogging. For this reason, the number of turns of the N-shaped hydrogen gas channel 30 is preferably 5 times or less and about 3 turns.

The operation of the fuel cell configured as described above will be described with reference to FIGS. 1 to 3, 7, and 8. FIG. 7 is a sectional view showing the operation of the fuel cell stack according to one embodiment of the present invention, FIG. 8 is a plan view of a conventional hydrogen gas channel (a), and a hydrogen gas channel of another embodiment of the present invention. It is a top view (b).
When air is supplied to the air flow path 50 and hydrogen gas is supplied to the hydrogen gas flow path 30 and a load is connected thereto, the hydrogen gas flows into the first bent portion 31c, the second hydrogen gas flow path 32, and the second bent. Flow through the third hydrogen gas flow path 33. Hydrogen contained in the hydrogen gas supplied to the N-shaped hydrogen gas flow channel 30 becomes hydrogen ions by the MEA 10 and reacts with oxygen contained in the air supplied to the air flow channel 50 to generate water.
In particular, as shown in FIG. 7, the water generated in the introduction facing part of the air flow path 50 flows from the introduction part of the air flow path 50 of the MEA 10 to the discharge part, and enters the hydrogen gas flow path part 20 via the MEA 10. It becomes the circulating water which flows into the introduction part of the air flow path 50 through the MEA 10 from the end of the hydrogen gas flow path section 20.
In addition, the water produced | generated except the introduction opposing part of the air flow path 50 also flows into the discharge part of the air flow path 50, flows into the hydrogen gas flow path part 20 via MEA10, and the terminal of the hydrogen gas flow path part 20 Circulating water flows from the part to the introduction part of the air flow path 50 via the MEA 10.

  At this time, the hydrogen gas flow in the introduction facing portion of the air flow channel 50 flows through the first bent portion 31c, the second hydrogen gas flow channel 32, the second bent portion 32c, and the third hydrogen gas flow channel 33. Caused by In the conventional straight I-shaped hydrogen gas flow path 130 (hereinafter referred to as the conventional straight flow path 130) having no number of turns shown in FIG. 8A, the first bent portion 31c, the second hydrogen gas Since the gas flow path 32 and the third hydrogen gas flow path 33 do not exist, the N-shaped hydrogen gas flow path 30 causes a larger amount of hydrogen gas to be introduced to the air flow path 50 than the straight flow path 130. It can flow.

The N-shaped hydrogen gas flow path 30 configured as described above includes first to third hydrogen gas flow paths 31, 32, 33 parallel to the air flow path 50, and first and second hydrogen gas flows. The first bent portion 31c that connects the first side-side ends of the gas flow paths 31 and 32 and the end of the second hydrogen gas flow path 32 face the hydrogen gas inlet 30a on the second side. Further, the second hydrogen gas flow path 32 has a second bent portion 32c that connects the second side end portions of the second and third hydrogen gas flow paths 32, 33. The end is opposed to and adjacent to the first bent portion 31c on the first side.
Thereby, the amount of hydrogen gas in the introduction facing portion of the air flow path 50 flows through the first bent portion 31c, the second hydrogen gas flow channel 32, the second bent portion 32c, and the third hydrogen gas flow channel 33. As a result, even in the type of fuel cell including the dead-end type hydrogen gas flow channel 30, the MEA 10 can be moderated by flowing a large amount of hydrogen gas to the introduction facing portion of the air flow channel 50 as compared with the conventional straight flow channel 130. Provides good wetting. Therefore, since the drying of the introduction part of the air flow path 50 can be prevented, a decrease in power generation performance can be prevented.

Further, as shown in FIG. 8B, a U-shaped hydrogen gas channel 230 may be provided instead of the N-shaped hydrogen gas channel 30. The U-shaped hydrogen gas flow path 230 includes a first hydrogen gas flow path 31 having a second side 10c side as a hydrogen gas inlet, and a second hydrogen having a terminal end parallel to the first hydrogen gas flow path 31. The first bent portion 31c that connects the gas channel 32 and the first side 10a side end of the first hydrogen gas channel 31 and the first side 10a side end of the second hydrogen gas channel 32. It is also good to have. In FIG. 8B, the same reference numerals as those in FIG.
According to the U-shaped hydrogen gas flow path 230 configured as described above, a large amount of hydrogen gas can be flowed to the introduction facing portion of the air flow path 50 as compared with the conventional straight flow path 130, and the hydrogen gas can be added. The pressure can be reduced. Therefore, drying of the introduction part of the air flow path 50 can be prevented.

As shown in FIG. 8B, it is preferable that the end of the second hydrogen gas flow path 32 is adjacent to the hydrogen gas inlet on the second side 10c side.
According to the hydrogen gas flow path 230 formed in this way, opposite directions are generated in the first and second hydrogen gas flow paths, respectively, so that a considerable amount of counter effect can be expected in the fuel electrode. Further, since the hydrogen gas flow path has a substantially U shape, a large number of hydrogen gas flow paths 230 can be provided in the same projected area. Accordingly, the hydrogen gas flow path portion 20 can be formed by arranging a large number of U-shaped hydrogen gas flow paths 230, so that the amount of hydrogen gas at the air flow introduction facing portion is increased and the introduction of the air flow path 50 is dried. Can be prevented appropriately.

<Experimental result>
Next, three types of hydrogen gas flow paths 30, 130, and 230 with different numbers of turns are prepared, and by measuring the characteristics of the fuel cell stack current density vs. cell voltage and current density vs. cell resistance by experiment, The degree of wetting of the introduction portion of the passage 50 was objectively determined, and it was confirmed that the fuel cell performance was improved.
The hydrogen gas flow path includes a number of conventional straight I-shaped hydrogen gas flow paths 130 shown in FIG. 8A, and a U-shaped hydrogen gas having one turn as shown in FIG. 8B. The flow path 230 and the hydrogen gas flow path 30 of this embodiment are applied, and the air flow path 50 on the cathode side is a straight flow path having the same shape as the hydrogen gas flow path 130.

Power generation conditions are temperature: 70 ° C, anode: non-humidified hydrogen pressure dead end (1kgf / cm2-G)
Cathode: Non-humidified air normal pressure flow (equivalent to stoichiometric 2), counter flow

FIG. 9 and FIG. 10 show characteristic curves obtained by measuring cell resistance and cell voltage corresponding to the current density of the fuel cell to which the three types of hydrogen gas flow paths 30, 130, and 230 are applied, respectively, under the above power generation conditions. . According to FIG. 9 and FIG. 10, the cell resistance of the fuel cell stack is decreased and the cell voltage is improved as the number of turns of the hydrogen gas flow path unit 20 is increased.
According to FIG. 9, in particular, the cell resistance decreases more clearly as the number of turns of the hydrogen gas flow path portion 20 increases. To clarify the tendency of cell resistance by hydrogen gas amount ratio Q _{d /} C _H2 in the air introducing face portion, and rearranging the hydrogen gas amount ratio Q _{d /} C _H2 in the horizontal axis as shown in FIG. 11, the hydrogen As the value of the gas amount ratio Q _d / C _H2 increases, the tendency to converge to around 4 mΩ, which is the cell resistance during full humidification (100% -RH), was observed. Therefore, it was confirmed that the wetting of the air introduction facing portion accelerated as the hydrogen gas amount ratio Q _d / _{CH 2} increased.
That is, by increasing the number of turns of the hydrogen gas flow path section 20, the amount of hydrogen gas in the portion facing the air introduction portion increases and functions as a water vapor carrier gas, thereby suppressing drying of the air introduction portion in the facing portion. This was confirmed by experiments.

Example 2
In the first embodiment, the width of the first hydrogen gas flow path 31 and the width of the second hydrogen gas flow path 32 are the same. However, the hydrogen gas flow path portion of the present embodiment has the first hydrogen gas flow path portion. The flow path 31 is formed narrower than the second hydrogen gas flow path 32. This is because the hydrogen gas amount _Qd is hardly influenced by the width of the first hydrogen gas flow path 31 as shown in FIG.
According to the hydrogen gas flow path portion configured in this way, the number of hydrogen gas flow paths is larger than that in the case where the first hydrogen gas flow path 31 and the second hydrogen gas flow path 32 have the same width. 30 can be provided, so that the total number of turns of the hydrogen gas flow path section 30 can be increased, and drying of the air introduction section of the air flow path 50 can be further suppressed.

Embodiment 3
The hydrogen gas flow path 30 of 1 of the above embodiment has a substantially N shape having two turns, but the hydrogen gas flow path 330 in this example has three turns as shown in FIG. A substantially W shape having 12, the same reference numerals as those in FIG. 3 denote the same parts, and a description thereof is omitted.
In FIG. 12, the substantially W-shaped hydrogen gas flow path 330 includes a fourth hydrogen gas flow path 334 parallel to the third hydrogen gas flow path 33 and the first side 10 a of the third hydrogen gas flow path 33. It has a U-shaped third bent portion 33c that connects the side end to the second side end of the fourth hydrogen gas flow path 33, and the end of the fourth hydrogen gas flow path 33 is the end of the fourth hydrogen gas flow path 33. The second side 10c side is adjacent to the first bent portion 31c.
According to the fuel cell using the substantially W-shaped hydrogen gas flow path 330 configured as described above, the amount of hydrogen gas at the introduction facing portion of the air flow path 50 is set to be higher than that of the N-shaped hydrogen gas flow path 30. The bent portion 33c and the fourth hydrogen gas flow channel increase by the amount of flow, and the drying of the introduction portion of the air flow channel 50 can be prevented more than the N-shaped hydrogen gas flow channel 30.

  The present invention is not limited to the embodiments of the invention and the description of the embodiments. Various modifications may be included in the present invention as long as those skilled in the art can easily conceive without departing from the description of the scope of claims.

It is sectional drawing of the single cell in the fuel cell stack which shows one Example of this invention. FIG. 2 is a detailed view of a hydrogen gas channel section shown in FIG. 1. It is a schematic diagram which shows the relationship between the hydrogen gas flow path and air flow path which are shown in FIG. FIG. 4 is a relationship diagram between a hydrogen gas flow path and a terminal minute region shown in FIG. 3. FIG. 5 is an enlarged view enlarging FIG. 4 for calculating a hydrogen gas amount Qd at a terminal portion of the hydrogen gas flow path portion. It is a curve figure which shows the relationship between hydrogen gas amount ratio and the number of turns of a hydrogen gas flow path. It is sectional drawing which shows operation | movement of the fuel cell stack by one Example of this invention. FIG. 6 is a plan view (a) of a conventional hydrogen gas flow channel and a plan view (b) of a hydrogen gas flow channel showing another embodiment of the present invention. It is a characteristic curve figure of the current density of the fuel cell which applied three types of hydrogen gas flow paths, respectively, and cell resistance. It is a characteristic curve figure of the current density of the fuel cell which applied three types of hydrogen gas flow paths, respectively, and cell voltage. It is a characteristic curve figure of hydrogen gas amount ratio vs. cell resistance of an air introduction facing part of a fuel cell to which each of three types of hydrogen gas flow paths is applied. It is a top view of the substantially W-shaped hydrogen gas flow path which has the number of turns of 3 times which shows the other Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 30 ... N-shaped hydrogen gas flow path 31 ... 1st hydrogen gas flow path 31c ... 1st bending part 32 ... 2nd hydrogen gas flow path 32c ... 2nd bending part 33 ... 2nd hydrogen gas flow path

Claims (4)

The fuel cell having an opposing first side and second side includes an air flow path for circulating air from the first side to the second side on the air electrode side of the fuel cell, and dead on the fuel electrode side. A fuel cell comprising an end-type hydrogen gas flow path,
The hydrogen gas flow path includes a first hydrogen gas flow path having the second side side as a hydrogen gas inlet, a second hydrogen gas flow path parallel to the first hydrogen gas flow path, A fuel cell comprising: a first bent portion connecting the first side-side end portion of the first hydrogen gas flow channel and the first side-side end portion of the second hydrogen gas flow channel. .   2. The fuel cell according to claim 1, wherein an end of the second hydrogen gas flow path is adjacent to the hydrogen gas inlet on the second side. The hydrogen gas flow path includes a third hydrogen gas flow path parallel to the second hydrogen gas flow path, the second side end of the second hydrogen gas flow path, and the third hydrogen gas. A second bent portion connecting the second side-side end portion of the gas flow path,
2. The fuel cell according to claim 1, wherein an end of the third hydrogen gas channel is adjacent to the first bent portion on the first side. 4. The fuel cell according to claim 1, wherein the first hydrogen gas passage is formed to be narrower than the second hydrogen gas passage. 5.

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