JP3673145B2 - Fuel cell stack and manufacturing method thereof - Google Patents

Description

【００４６】
実験結果を図１４に示す。図１４は縦軸にせん断接着強さ（ｋｇｆ／ｃｍ２）を、横軸に使用した材料を示したものである。この実験結果によれば、熱硬化型フッ素系シール剤１を用いた場合には、セパレータの材料としてモールドカーボン、焼成カーボン、ＳＵＳ３１６（ステンレス材）、ＡＬのいずれを用いた場合であっても、塗布した後加熱して硬化させてから上記の引張り速度でテストした際にセパレータは破損してもどの接着部位においても剥がれは生じなかった。また、熱硬化型シリコンシール剤（付加反応タイプ）を用いた場合でも同様の結果が得られた。
【００４７】
ここで、上記熱硬化型シリコンシール剤を用いた場合には、モールドカーボン、燒結カーボンに対するせん断接着強さは最低で２ｋｇｆ／ｃｍ２であったので、単位燃料電池もしくは数組の単位燃料電池単位でモジュール化する場合に、セパレータとのせん断接着強さが２ｋｇｆ／ｃｍ２以上であれば、取り扱い上剥離することなく積層、脱着が可能と判断できる。つまり、接着性シールとはせん断接着強さが２ｋｇｆ／ｃｍ２以上のものを示す。
【００４８】
一方、熱硬化型フッ素系シール剤２においては接着官能基をほとんど有さないタイプを使用したので、実際に焼成カーボンセパレータやモールドカーボンセパレータに塗布し、単位燃料電池として液状シールを硬化させて組立てた後に手でセパレータを横方向に引き剥がそうとすると簡単に引き剥がせた。
上記熱硬化型フッ素系シール剤２の上記各セパレータ材に対するせん断接着強さは、０〜０．５ｋｇｆ／ｃｍ２であることから、０．５ｋｇｆ／ｃｍ２以下であれば、燃料電池スタックに不良が発覚したとしても、容易に不良な単位電池１０を取り除くことができる。
すなわち、非接着シールとはせん断接着強さが０．５ｋｇｆ／ｃｍ２以下であるものを示す。また、せん断接着強さが０．５〜２ｋｇｆ／ｃｍ２の範囲はものは低接着シールとして非接着シールに含めるものとする。
【００４９】
ここで、前述したように上記非接着シール、接着シールは、使用される時点におけるせん断接着強さにより判別されるのであって、接着剤の種類により分類するものではない。したがって、塗布した後その部分にセパレータを密着して加熱硬化した場合にせん断接着強さが２ｋｇｆ／ｃｍ２以上である接着性のシール材であっても、塗布して加熱硬化した後一定時間放置してから、セパレータを密着して使用すると、その部分におけるせん断接着強さが２ｋｇｆ／ｃｍ２よりも小さくなっている場合には、非接着性シール（低接着シール）となるのである。
【００５０】
上記実施形態によれば、前記第１セパレータ１４及び第２セパレータ１６間には燃料電池セル１２を介して前記燃料電池セル１２の電極反応面を構成するアノード電極２２及び第２拡散層２６と、カソード電極２０及び第１拡散層２４との外周部分への反応ガスの漏れを防止するために接着性のシールである液状シールＳを設け、隣接する第１セパレータ１４の面１４ｂと第２セパレータ１６の面１６ｂとの間には非接着性のシールである液状シールＳ１、あるいは、固体シールＫＳ１を設けたため、積層された前記単位燃料電池１０間においては、非接着性のシールである液状シールＳ１を塗布している部分において互いに隣接する第１セパレータ１４と第２セパレータ１６を容易に分離することができる。
【００５１】
したがって、例えば、第１セパレータ１４、第２セパレータ１６が破損するなどして単位燃料電池１０を交換しなければならないような場合に、隣接する第１セパレータ１４と第２セパレータ１６との間において上記分解再組立てを容易に行なうことができるリビルド性に優れている。尚、ここで燃料電池セル１２を挟持する第１セパレータ１４と第２セパレータ１６との間には接着性の液状シールＳが用いられているため、分解再組立て時にこの部分において剥がれを起こすようなことはない。
【００５２】
また、前記固体高分子電解質膜１８の周囲に設けたはみ出し部１８ａに直接的に密着する液状シールＳが固体高分子電解質膜１８と第１，第２セパレータ１４，１６との間で形状変化してシール寸法のバラツキに追従し、各溝部２８，３０，３４，３５内において一定の面圧を確保した状態で両者間に隙間なく介在して両者間の気密性を確保することができるため、第１，第２セパレータ１４，１６と燃料電池セル１２との間で全周に渡って均一なシール反力が得られ、均一なシール性を確保することができる。
したがって、液状シールＳによる寸法誤差に対する追従性の良さから、第１，第２セパレータ１４，１６や燃料電池セル１２のとりわけ厚さ方向での寸法管理を厳密に行なう必要がなく、寸法精度管理が容易となりコストダウンを図ることができる。
【００５３】
また、第１，第２セパレータ１４，１６の溝部２８に塗布された液状シールＳは、溝部２８内で一定の幅を維持した状態で、前記固体高分子電解質膜１８のはみ出し部１８ａに密着して、シール寸法に応じて変形することができるため、第１，第２セパレータ１４，１６により燃料電池セル１２を挟持するだけで、シール部分における気密性を確保できる。
【００５４】
そして、第１，第２セパレータ１４，１６と固体高分子電解質膜１８のはみ出し部１８ａとの間のシール寸法のバラツキを液状シールＳが吸収することにより、各セパレータ１４，１６に偏った力が作用するのを防止できるため、各セパレータ１４，１６の薄肉化を図ることができ、全体として軽量かつ小型化することができる。よって配置スペースに制限があり、できる限り各セパレータ１４，１６を薄型化する必要がある車両用として用いられた場合に好適である。
【００５５】
また、液状シールＳを固体高分子電解質膜１８に対して直接的に密着させるため、例えば、燃料電気セル１２の周囲に額縁状の枠体を設ける場合に比較して部品点数、組付け工数を削減できる点で有利である。そして、固体高分子電解質膜１８に対する液状シールＳの面圧も均一になり、固体高分子電解質膜１８が偏った力を受けることもない。尚、固体高分子電解質膜１８が波を打ったような場合でもこれに合わせて変形できるため、固体高分子電解質膜１８にしわが発生するようなこともない。
【００５６】
【発明の効果】
以上説明してきたように、請求項１に記載した発明によれば、積層された前記単位燃料電池間においては、隣接するセパレータ間に非接着性シールが使用されているため、この部分において容易に両セパレータを分離することができるため、例えば、燃料電池スタックを組立てた後において、単位燃料電池を交換したいような場合においても容易に該当する単位燃料電池を取り外すことができ、リビルド性に優れているという効果がある。また、このように単位燃料電池を取り外す場合には、一対のセパレータ間には接着性シールが使用されているため電極膜構造体との間において剥離が生ずることはなく、問題がない単位燃料電池内において各拡散電極とセパレータとの間で剥離が起きることはない。
【図面の簡単な説明】
【図１】 この発明の実施形態の全体組立図である。
【図２】 この発明の実施形態の要部分解斜視図である。
【図３】 図２のＡ−Ａ断面図である。
【図４】 この発明の実施形態の第１セパレータの図２のＢ矢視図である。
【図５】 この発明の実施形態の第２セパレータの図２のＣ矢視図である。
【図６】 この発明の実施形態の第２セパレータの図２のＤ矢視図である。
【図７】 この発明の実施形態の図３の部分拡大図である。
【図８】 この発明の実施形態の積層手順の第１態様を示す説明図である。
【図９】 この発明の実施形態の積層手順の第２態様を示す説明図である。
【図１０】 この発明の実施形態の積層手順の第３態様を示す説明図である。
【図１１】 この発明の実施形態の積層手順の第４態様を示す説明図である。
【図１２】 実験状況を示す側面説明図である。
【図１３】 図１２のＸ矢視図である。
【図１４】 実験結果を示すグラフ図である。
【図１５】 従来技術の断面図である。
【符号の説明】
１０ 単位燃料電池
１２ 燃料電池セル（電極膜構造体）
１４ 第１セパレータ
１６ 第２セパレータ
１８ 固体高分子電解質膜
２０ カソード電極
２２ アノード電極
２４ 第１ガス拡散層
２６ 第２ガス拡散層
Ｎ 燃料電池スタック
Ｓ 液状シール（接着性シール）
Ｓ１ 液状シール（非接着性シール）[0001]
BACKGROUND OF THE INVENTION
  The present invention is configured by laminating a plurality of unit fuel cells in which an electrode membrane structure composed of a solid polymer electrolyte membrane and anode-side diffusion electrodes and cathode-side diffusion electrodes on both sides thereof is sandwiched by a pair of separators. In particular, the fuel cell stack is easy to perform replacement work for each unit fuel cell.And its manufacturing methodIt is about.
[0002]
[Prior art]
In a fuel cell stack, an electrode membrane structure composed of a solid polymer electrolyte membrane and anode-side diffusion electrodes and cathode-side diffusion electrodes on both sides thereof is sandwiched between a pair of separators to constitute a unit fuel cell. Some of these unit fuel cells are stacked. In the unit fuel cell, when fuel gas (for example, hydrogen gas) is supplied to the reaction surface of the anode side diffusion electrode, hydrogen is ionized here and moves to the cathode side diffusion electrode side through the solid polymer electrolyte membrane. Electrons generated during this time are taken out to an external circuit and used as direct current electric energy. Since an oxidizing gas (for example, air containing oxygen) is supplied to the cathode electrode, hydrogen ions, electrons, and oxygen react to generate water.
[0003]
An example of this will be described with reference to FIG. 15. In the figure, 1 indicates a solid polymer electrolyte membrane, and the solid polymer electrolyte membrane 1 is sandwiched between gas diffusion electrodes (anode side diffusion electrode and cathode side diffusion electrode) 2 and 3 from both sides. Thus, the fuel battery cell 4 is configured. The fuel cell 4 is sandwiched between separators 6 and 6 via a carbon plate 5 disposed on the periphery, and the separator 6 and the fuel cell 4 are joined by a sheet-like double-sided adhesive 7 to form a unit fuel cell. A plurality of unit fuel cells are stacked to form a fuel cell stack (see Japanese Patent Application Laid-Open No. 9-289029).
[0004]
[Problems to be solved by the invention]
  In the conventional fuel cell stack, each fuel cell 4 and the separators 6 and 6 are simply bonded with the sheet-like double-sided adhesive 7 to constitute a unit fuel cell. For example, when it is necessary to replace a part of the solid polymer electrolyte membrane 1 or the separator 6 at the time of assembling, both of them can be laminated at the part of the double-sided adhesive 7 corresponding to the part. There is a problem that it takes time to work.
  When both members are peeled off at the application site of the double-sided adhesive 7 as described above, there is a problem in that distortion occurs at other sites than the site to be replaced.
  Accordingly, the present invention provides a fuel cell stack that facilitates replacement work for each unit fuel cell.And its manufacturing methodIs to provide.
[0005]
[Means for Solving the Problems]
  In order to solve the above-mentioned problem, the invention described in claim 1 is directed to a solid polymer electrolyte membrane (for example, the solid polymer electrolyte membrane 18 in the embodiment) as an anode side diffusion electrode (for example, the anode electrode 22 in the embodiment and An electrode membrane structure (for example, the fuel cell 12 in the embodiment) sandwiched between the second diffusion layer 26) and the cathode side diffusion electrode (for example, the cathode electrode 20 and the first diffusion layer 24 in the embodiment). Is sandwiched between a pair of separators (for example, the first separator 14 and the second separator 16 in the embodiment) to form a unit fuel cell (for example, the unit fuel cell 10 in the embodiment), and a plurality of unit fuel cells are formed. In a fuel cell stack configured by stacking (for example, the fuel cell stack N in the embodiment), between the pair of separators, An adhesive seal (for example, the liquid seal S in the embodiment) is provided to prevent leakage of reaction gas from the electrode reaction surface of the electrode membrane structure to the outer peripheral portion of the anode side diffusion electrode or the cathode side diffusion electrode. A non-adhesive seal (for example, the liquid seal S1 in the embodiment) is provided between adjacent separators of the unit fuel cell., Making it easy to replace each unit fuel cellIt is characterized by that.
[0006]
  With this configuration, since the non-adhesive seal is used between the adjacent separators between the stacked unit fuel cells, both separators can be easily separated at this portion, and the unit fuel cells can be separated. Can be removed. Thus, when removing a unit fuel cell, since the adhesive seal is used between a pair of separators, peeling does not arise between electrode membrane structures.
  The invention described in claim 2 is the one described in claim 1, wherein the non-adhesive seal is obtained by press-bonding the adhesive seal and heating and curing it.
  Invention of Claim 3 is a manufacturing method of the fuel cell stack of Claim 1, Comprising: The said non-adhesive seal is manufactured by crimping | bonding and heating and hardening the said adhesive seal. It is characterized by.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a fuel cell stack N according to an embodiment of the present invention.
The fuel cell stack N is formed by laminating a plurality of unit fuel cells 10 each composed of a fuel cell (electrode membrane structure) 12 and a first separator 14 and a second separator 16 sandwiching the fuel cell (electrode membrane structure) 12. First and second end plates 80 and 82 are disposed at both ends of the fuel cell stack N in the stacking direction of the unit fuel cells 10, and the first and second end plates 80 and 82 are integrated with each other via a tie rod 84. Tightened and fixed.
[0008]
The first end plate 80 has a hole 94 communicating with an outlet-side oxidant gas communication hole 38b, which will be described later, and communicates with the hole 94 via a joint 96 in the first end plate 80. A manifold tube 98 is connected. The first end plate 80 is formed with a hole 104 communicating with an outlet-side fuel gas communication hole 36b, which will be described later, and a manifold hole pipe configured similarly to the manifold tube 98 described above. The body 106 is connected.
[0009]
The fuel cell 12 constituting the unit fuel cell 10 together with the first and second separators 14 and 16 sandwiches the solid polymer electrolyte membrane 18 and the solid polymer electrolyte membrane 18 as shown in FIGS. And the cathode electrode 20 and the anode electrode 22 are provided with a first gas made of, for example, porous carbon cloth or porous carbon paper which is a porous layer. A diffusion layer 24 and a second gas diffusion layer 26 are provided. Here, a perfluorosulfonic acid polymer is used as the solid polymer electrolyte membrane 18. The cathode electrode 20 and the anode electrode 22 are mainly composed of Pt. The cathode electrode 20 and the first gas diffusion layer 24 constitute a cathode side diffusion electrode, and the anode electrode 22 and the second gas diffusion layer 24 constitute an anode side diffusion electrode.
[0010]
The solid polymer electrolyte membrane 18 is provided with a protruding portion 18a that protrudes from the outer periphery of the cathode electrode 20 and the anode electrode 22 that are disposed therebetween, and the first and first portions from both sides are located at positions corresponding to the protruding portion 18a. A liquid seal S (described later) applied to the two separators 14 and 16 is in direct contact.
[0011]
As shown in FIG. 4, the first separator 14 has an inlet-side fuel gas communication hole for allowing a fuel gas such as a hydrogen-containing gas to pass through the upper ends of the lateral ends located in the outer peripheral edge within the plane. 36a and an inlet side oxidant gas communication hole 38a for allowing an oxidant gas, which is an oxygen-containing gas or air, to pass therethrough.
An inlet-side cooling medium communication hole 40a for passing a cooling medium such as pure water, ethylene glycol, or oil, and an outlet for allowing the used cooling medium to pass through are provided at the center of both lateral ends of the first separator 14. A side cooling medium communication hole 40b is provided.
[0012]
Further, an outlet-side fuel gas communication hole 36b for allowing the fuel gas to pass therethrough and an outlet for allowing the oxidant gas to pass to the lower portions of both ends in the lateral direction located in the outer peripheral edge portion within the plane of the first separator 14 The side oxidant gas communication hole 38b is provided so as to be diagonal to the inlet side fuel gas communication hole 36a and the inlet side oxidant gas communication hole 38a.
[0013]
As shown in FIG. 2, on the surface 14a of the first separator 14 facing the cathode electrode 20, a plurality of, for example, six independent first oxidizers are provided in the vicinity of the inlet-side oxidant gas communication hole 38a. The gas flow path groove 42 is provided in the direction of gravity while meandering in the horizontal direction. The first oxidant gas flow channel 42 joins the three second oxidant gas flow channels 44, and the second oxidant gas flow channel 44 is adjacent to the outlet side oxidant gas communication hole 38b. It is terminated.
[0014]
As shown in FIG. 4, the first separator 14 penetrates through the first separator 14, and one end communicates with the inlet-side oxidant gas communication hole 38a on the surface 14b opposite to the surface 14a. A first oxidant gas connection channel 46 whose end communicates with the first oxidant gas channel groove 42 on the surface 14a side, and one end communicates with the outlet side oxidant gas communication hole 38b on the surface 14b side, A second oxidant gas connection channel 48, the other end of which communicates with the second oxidant gas channel groove 44 on the surface 14a side, is provided through the first separator 14.
[0015]
As shown in FIG. 5 and FIG. 6, similarly to the first separator 14, the inlet-side fuel gas communication hole 36 a and the inlet are provided on both ends in the lateral direction within the plane of the second separator 16 and located at the outer peripheral edge. A side oxidant gas communication hole 38a, an inlet side cooling medium communication hole 40a, an outlet side cooling medium communication hole 40b, an outlet side fuel gas communication hole 36b, and an outlet side oxidant gas communication hole 38b are formed.
In the surface 16a of the second separator 16, a plurality of, for example, six first fuel gas passage grooves 60 are formed in the vicinity of the inlet side fuel gas communication hole 36a. The first fuel gas flow channel 60 extends in the direction of gravity while meandering in the horizontal direction, and merges with the three second fuel gas flow channels 62 to form the second fuel gas flow channel 62. Terminates in the vicinity of the outlet side fuel gas communication hole 36b.
The second separator 16 has a first fuel gas connection channel 64 communicating the inlet side fuel gas communication hole 36a from the surface 16b side to the first fuel gas channel groove 60, and an outlet side fuel gas communication hole 36b. A second fuel gas connection channel 66 communicating with the second fuel gas channel groove 62 from the 16b side is provided through the second separator 16.
[0016]
As shown in FIGS. 3 and 6, a plurality of mainstreams constituting the cooling medium flow path are formed on the surface 16 b of the second separator 16 in the vicinity of the inlet side cooling medium communication hole 40 a and the outlet side cooling medium communication hole 40 b. Road grooves 72a and 72b are formed. Between the main flow path grooves 72a and 72b, branch flow path grooves 74 that branch into a plurality of lines are provided extending in the horizontal direction.
The second separator 16 has a first cooling medium connection channel 76 that communicates the inlet side cooling medium communication hole 40a and the main channel groove 72a, and an outlet side cooling medium communication hole 40b and the main channel groove 72b that communicates with each other. A second cooling medium connection channel 78 is provided through the second separator 16.
[0017]
Here, as shown in FIG. 5, a surface 16a facing the anode electrode 22 of the second separator 16 sandwiching the solid polymer electrolyte membrane 18 is located at a position corresponding to the protruding portion 18a of the solid polymer electrolyte membrane 18. A groove portion 28 is provided in the groove portion 28, and an adhesive liquid seal (adhesive seal) S is applied to the groove portion 28. Further, the inlet side fuel gas communication hole 36a, the inlet side oxidant gas communication hole 38a, the inlet side cooling medium communication hole 40a, the outlet side cooling medium communication hole 40b, and the outlet side fuel gas communication hole of the surface 16a of the second separator 16 are provided. A groove 30 is also formed around 36 b and the outlet side oxidant gas communication hole 38 b, and an adhesive liquid seal (adhesive seal) S is also applied to the groove 30. However, as for the groove part 30, since the first separator 14 and the second separator 16 are integrally bonded by an adhesive seal applied to the groove part 28, a non-adhesive seal may be used.
Here, the grooves 30 around the inlet side cooling medium communication hole 40a and the outlet side cooling medium communication hole 40b are formed so as to surround the first cooling medium connection channel 76 and the second cooling medium connection channel 78, respectively. Has been.
[0018]
Further, as shown in FIG. 2, the groove portion 28 and the groove portion of the surface 16a of the second separator 16 are also formed on the surface 14a facing the cathode electrode 20 of the first separator 14 that sandwiches the fuel cell 12 together with the second separator 16. A groove 28 and a groove 30 are formed at positions corresponding to 30, and an adhesive liquid seal (adhesive seal) S is applied to each of the grooves 28 and 30. Therefore, as shown in FIGS. 3 and 7, each liquid seal S applied to the grooves 28 and 30 between the first separator 14 and the second separator 16 sandwiching the fuel battery cells 12 is replaced with the liquid seal of the groove 28. In S, the protruding portion 18a is sandwiched at positions facing each other and directly adhered to each other to seal the periphery of the fuel cell 12, and in the liquid seal S of the groove portion 30, the communication holes 36a, The periphery of 36b, 38a, 38b, 40a, 40b is sealed.
[0019]
As shown in FIG. 6, the surface 16 b of the second separator 16 is a position facing the surface 14 b of the first separator 14 when a plurality of unit fuel cells 10 are stacked, and the branch flow channel groove 74. A groove portion 34 is provided to surround the periphery of the substrate, and a non-adhesive liquid seal (non-adhesive seal) S1 is applied to the groove portion 34. Further, the inlet side fuel gas communication hole 36a, the inlet side oxidant gas communication hole 38a, the inlet side cooling medium communication hole 40a, the outlet side cooling medium communication hole 40b, and the outlet side fuel gas communication hole of the surface 16b of the second separator 16 are provided. A groove 35 is also formed around 36b and the outlet-side oxidant gas communication hole 38b, and a non-adhesive liquid seal (non-adhesive seal) S1 is applied to the groove 35.
[0020]
Here, the grooves 35 around the inlet side fuel gas communication hole 36a and the outlet side fuel gas communication hole 36b are formed so as to surround the first fuel gas connection channel 64 and the second fuel gas connection channel 66, respectively. Has been. A groove 35 around the inlet-side oxidant gas communication hole 38a and the outlet-side oxidant gas communication hole 38b is connected to the inlet-side oxidant gas communication hole 38a and the outlet-side oxidant gas communication hole of the surface 14b of the first separator 14. It is provided so as to surround the hole 38b.
[0021]
In this way, when the unit fuel cells 10 are stacked, if the surface 14b of the first separator 14 and the surface 16b of the second separator 16 are polymerized, the inlet-side fuel gas communication hole 36a, the inlet-side oxidant gas communication hole 38a, inlet-side cooling medium communication hole 40a, outlet-side cooling medium communication hole 40b, outlet-side fuel gas communication hole 36b, outlet-side oxidant gas communication hole 38b, and branch flow channel groove 74 around the second separator 16 side The liquid seals S <b> 1 are in close contact with the surface 14 b of the first separator 14, thereby ensuring water tightness between the first separator 14 and the second separator 16.
[0022]
Here, the liquid seals S and S1 are made of thermosetting fluorine-based or thermosetting silicon, have a viscosity that does not change the cross-sectional shape in the applied state, and are cured with a certain degree of elasticity after application. Is. Here, as the liquid seal S which is the adhesive seal, for example, a thermosetting fluorine-based sealant or a thermosetting silicone sealant having a hydroxyl group involved in adhesion in a side chain described later can be used. As the liquid seal S1 which is the non-adhesive seal, for example, a thermosetting fluorine-based sealant described later can be used.
[0023]
The operation of the unit fuel cell 10 configured as described above will be described below.
The unit fuel cell 10 is supplied with a fuel gas, for example, a gas containing hydrogen obtained by reforming hydrocarbons, and is supplied with air or an oxygen-containing gas (hereinafter also simply referred to as air) as an oxidant gas. A cooling medium is supplied to cool the power generation surface. The fuel gas supplied to the inlet side fuel gas communication hole 36a of the unit fuel cell 10 moves from the surface 16b side to the surface 16a side via the first fuel gas connection channel 64, as shown in FIG. The first fuel gas channel groove 60 formed on the surface 16a side is supplied.
[0024]
The fuel gas supplied to the first fuel gas channel groove 60 moves in the direction of gravity while meandering in the horizontal direction along the surface 16a of the second separator 16. At that time, the hydrogen-containing gas in the fuel gas is supplied to the anode side electrode 22 of the fuel cell 12 through the second gas diffusion layer 26. Unused fuel gas is supplied to the anode-side electrode 22 while moving along the first fuel gas flow channel groove 60, while the second fuel gas flow channel 62 shown in FIG. After being introduced into the fuel gas connection channel 66 and moving to the surface 16b side, it is discharged to the outlet side fuel gas communication hole 36b shown in FIG.
[0025]
Further, the air supplied to the inlet side oxidant gas communication hole 38a in the unit fuel cell 10 is communicated with the first side oxidant gas communication hole 38a of the first separator 14 as shown in FIG. It is introduced into the first oxidant gas channel groove 42 via the connection channel 46. While the air supplied to the first oxidant gas flow channel 42 moves in the gravity direction while meandering in the horizontal direction, the oxygen-containing gas in the air is supplied from the first gas diffusion layer 24 to the cathode side electrode 20. Is done. On the other hand, unused air is discharged from the second oxidant gas connection channel 48 to the outlet side oxidant gas communication hole 38b via the second oxidant gas channel groove 44 as shown in FIG. As a result, power is generated by the unit fuel cell 10 and, for example, power is supplied to a motor (not shown).
[0026]
Furthermore, the cooling medium supplied to the unit fuel cell 10 is introduced into the inlet side cooling medium communication hole 40a as shown in FIG. 2, and then the first cooling medium of the second separator 16 as shown in FIG. It is supplied to the main channel groove 72a on the surface 16b side through the connection channel 76. The cooling medium cools the power generation surface of the fuel cell 12 through a plurality of branch flow channel grooves 74 branched from the main flow channel groove 72a, and then merges with the main flow channel groove 72b. Then, the used cooling medium is discharged from the outlet side cooling medium communication hole 40 b through the second cooling medium connection channel 78.
[0027]
Next, each aspect of the lamination | stacking procedure of the 1st, 2nd separators 14 and 16 is demonstrated. In the following description, the liquid seals S and S1 applied to the groove 28 and the groove 34 will be described. When the liquid seal S is applied to the groove 28, the liquid seal S applied to the groove 30 and the groove The description of the liquid seal S1 applied to the groove 35 when the liquid seal S1 is applied to the groove 34 will be omitted.
Further, when the liquid seals S and S1 are shown in a circular cross section, they are in a coated state, and when they are shown in a quadrangular shape (in the case shown in FIG. 7) or a hexagonal cross section, they are in a state of being pressed and cured. And what is described as non-adhesive in the following description includes those having low adhesiveness described later.
[0028]
In the first mode shown in FIG. 8, first, the liquid seal S <b> 1 is applied to the groove 34 of the surface 16 b of the second separator 16. This liquid seal S1 is an adhesive seal. Next, the liquid seal S1 applied to the groove 34 is pressure-bonded using a release jig R (shown by a chain line) having a Teflon coating, and is heated and cured. As a result, the adhesive seal is cured and the liquid seal S1 adhered (Sa side) to the groove 34 is shear-bonding strong on the release jig R side (Sb side) as described later. And the non-adhesive seal. Here, the non-adhesive seal and the adhesive seal are discriminated by the shear adhesive strength at the time of use, and are not classified by the type of adhesive.
Then, a liquid seal S is applied to the groove 28 side of the second separator 16, and the fuel cell 12 is sandwiched between the first separator 14 having the other liquid seal S applied to the groove 28, and each liquid The assembly of the unit fuel cell 10 is completed by heating and curing the liquid seal S with the solid polymer electrolyte membrane 18 sandwiched between the seals S.
[0029]
Therefore, this aspect can be expressed as follows as a manufacturing method of the fuel cell stack N.
The solid polymer electrolyte membrane (for example, the solid polymer electrolyte membrane 18 in the embodiment) is replaced with the anode side diffusion electrode (for example, the anode electrode 22 and the second diffusion layer 26 in the embodiment) and the cathode side diffusion electrode (for example, in the embodiment). An electrode film structure (for example, the fuel cell 12 in the embodiment) configured to be sandwiched between the cathode electrode 20 and the first diffusion layer 24) is paired with a pair of separators (for example, one first separator 14 in the embodiment). And the other second separator 16) to form a unit fuel cell (for example, the unit fuel cell 10 in the embodiment), and a fuel cell stack (for example, implementation) configured by stacking a plurality of the unit fuel cells. In the method of manufacturing the fuel cell stack N) in the embodiment, the surface of the other separator, the one of the adjacent separators An adhesive liquid seal (for example, the liquid seal S1 in the embodiment) is applied to a predetermined position (for example, the groove 34 in the embodiment) (for example, the surface 16b in the embodiment), and a releasable jig (for example, The adhesive seal is pressed and cured by a mold release tool R) in the embodiment, the adhesive seal is made into a non-adhesive liquid seal, and the electrode film structure is the surface of the other separator. An adhesive liquid seal (for example, the liquid seal S in the embodiment) is applied to a predetermined position (for example, the groove 28 in the embodiment) of the body-side surface (for example, the surface 16a in the embodiment), and the surface of the one separator Between the adhesive liquid seal applied to a predetermined position (for example, the groove 28 in the embodiment) of the surface on the electrode film structure side (for example, the surface 14a in the embodiment). Sandwiching the electrode membrane structural body was heated cured, it is characterized in that a laminate of these.
[0030]
By comprising in this way, since the liquid seal of the other separator and one separator laminated | stacked on this peel easily, there exists an effect which becomes easy to disassemble and reassemble.
[0031]
Therefore, when the fuel cell stack N is manufactured by stacking the above units, the first separator 14 can be easily peeled off at the portion of the liquid seal S1 that is pressure-bonded and solidified using the mold release tool R. For example, when the specific solid polymer electrolyte membrane 18 must be replaced, or when the first separator 14 and the second separator 16 must be replaced, the unit fuel cell 10 can be attached and removed. It is excellent in rebuildability that can be easily disassembled and reassembled. Here, since an adhesive liquid seal S is used between the first separator 14 and the second separator 16 that sandwich the fuel cell 12, it is difficult to cause peeling at this portion during disassembly and reassembly. Absent.
Further, since the liquid seal S1 is bonded to the groove 34 of the second separator 16, it does not fall off during assembly.
[0032]
Next, the second mode shown in FIG. 9 will be described. First, the liquid seal S1 which is a non-adhesive seal is applied to the groove 34 of the surface 16b of the second separator 16. Next, the surface 14b of the first separator 14 is overlapped with the surface 16b of the second separator 16, and the liquid seal S1 is cured. Then, a liquid seal S that is an adhesive seal is applied to the groove 28 of the surface 16a of the second separator 16, and the liquid seal S is applied to the groove 28 in advance between the first separator 14 and the second separator 16. The unit fuel cell 10 can be assembled by sandwiching the fuel cell 12 and heating and curing the liquid seal S.
[0033]
Therefore, this aspect can be expressed as follows as a manufacturing method of the fuel cell stack N.
The solid polymer electrolyte membrane (for example, the solid polymer electrolyte membrane 18 in the embodiment) is replaced with the anode side diffusion electrode (for example, the anode electrode 22 and the second diffusion layer 26 in the embodiment) and the cathode side diffusion electrode (for example, in the embodiment). An electrode film structure (for example, the fuel cell 12 in the embodiment) configured to be sandwiched between the cathode electrode 20 and the first diffusion layer 24) is paired with a pair of separators (for example, one first separator 14 in the embodiment). And the other second separator 16) to form a unit fuel cell (for example, the unit fuel cell 10 in the embodiment), and a fuel cell stack (for example, implementation) configured by stacking a plurality of the unit fuel cells. In the method of manufacturing the fuel cell stack N) in the embodiment, the surface of the other separator, the one of the adjacent separators A non-adhesive liquid seal (for example, the liquid seal S1 in the embodiment) is applied to a predetermined position (for example, the groove 34 in the embodiment) (for example, the surface 16b in the embodiment), and one separator is overlaid thereon. In addition, the liquid seal is cured, and an adhesive liquid is applied to a predetermined position (for example, the groove 28 in the embodiment) of the surface of the other separator, that is, the surface on the electrode film structure (for example, the surface 16a in the embodiment). A seal (for example, the liquid seal S in the embodiment) is applied, and a predetermined position (for example, the groove 28 in the embodiment) of the surface on the electrode film structure side (for example, the surface 14a in the embodiment) among the surfaces of the one separator. The fuel cell 12 is sandwiched between the adhesive liquid seal and the adhesive liquid seal applied to the substrate and heat-cured, and these are laminated.
[0034]
By comprising in this way, since the liquid seal of the other separator and one separator laminated | stacked on this peel easily, there exists an effect which becomes easy to disassemble and reassemble.
[0035]
Therefore, also in this aspect, when the unit is laminated to manufacture the fuel cell stack N, the adjacent first separator 14 and second separator 16 are sealed by the liquid seal S1 which is a non-adhesive seal. Therefore, disassembly and reassembly with this part as a boundary is easy. In addition, since an adhesive liquid seal S is used between the first separator 14 and the second separator 16, peeling does not occur at this portion.
[0036]
Next, the third mode shown in FIG. 10 will be described. First, a liquid seal S that is an adhesive seal is applied to the groove 28 of the first separator 14, and the liquid seal S that is an adhesive seal is applied to the groove 28 of the surface 16 a of the second separator 16. A liquid seal S1 that is a non-adhesive seal is applied to the groove 34. Then, the fuel battery cell 12 and the second separator 16 are sandwiched between the first separators 14 and a plurality of sets are stacked and then heated and cured.
[0037]
Therefore, this aspect can be expressed as follows as a manufacturing method of the fuel cell stack N.
The solid polymer electrolyte membrane (for example, the solid polymer electrolyte membrane 18 in the embodiment) is replaced with the anode side diffusion electrode (for example, the anode electrode 22 and the second diffusion layer 26 in the embodiment) and the cathode side diffusion electrode (for example, in the embodiment). An electrode film structure (for example, the fuel cell 12 in the embodiment) configured to be sandwiched between the cathode electrode 20 and the first diffusion layer 24) is paired with a pair of separators (for example, one first separator 14 in the embodiment). And the other second separator 16) to form a unit fuel cell (for example, the unit fuel cell 10 in the embodiment), and a fuel cell stack (for example, implementation) configured by stacking a plurality of the unit fuel cells. In the manufacturing method of the fuel cell stack N) in the embodiment, the surface on the electrode membrane structure side (for example, implementation) of the surfaces of one separator An adhesive liquid seal (for example, the liquid seal S in the embodiment) is applied to a predetermined position (for example, the groove 28 in the embodiment) of the surface 14a) in the state, and the surface of the other separator is adjacent to one of the adjacent surfaces. A non-adhesive liquid seal (for example, the liquid seal S1 in the embodiment) is applied to a predetermined position (for example, the groove 34 in the embodiment) of the separator-side surface (for example, the surface 16b in the embodiment), and the other separator An adhesive liquid seal (for example, the liquid seal S in the embodiment) is applied to a predetermined position (for example, the groove 28 in the embodiment) of the surface on the electrode film structure side (for example, the surface 16a in the embodiment). The electrode film structure and the other separator are sandwiched between one separator and heat-cured in a state where a plurality of sets are laminated.
[0038]
By comprising in this way, since the liquid seal of the other separator and one separator laminated | stacked on this peel easily, there exists an effect which becomes easy to disassemble and reassemble. In addition, since the adhesive and non-adhesive liquid seals can be cured at one time without dividing the process into two as in the first and second embodiments, the process can be reduced and the productivity is excellent. There is an effect that.
[0039]
Therefore, also in this aspect, when the unit is laminated to manufacture the fuel cell stack N, the adjacent first separator 14 and second separator 16 are bonded by the liquid seal S1 that is a non-adhesive seal. Therefore, disassembly and reassembly for each unit fuel cell 10 is easy. Further, since the liquid seal S sandwiching the fuel battery cell 12 does not peel off, it is the same as the above embodiments in that peeling does not occur at this portion. In this aspect, since the liquid seals S and S1 can be cured at once without dividing the process into two as in the first and second aspects, the process can be reduced and the productivity is excellent. .
[0040]
Next, the 4th aspect shown in FIG. 11 is demonstrated. First, the liquid seal S which is an adhesive seal is applied to the groove 28 on the surface 16a of the second separator 16. Then, the fuel cell 12 is sandwiched between the second separator 16 and the first separator 14 in which the liquid seal S, which is an adhesive seal, is applied to the groove 28 in advance. The unit fuel cell 10 is assembled by curing. Then, a solid seal KS1 that is a non-adhesive seal is set in the groove 34 of the surface 16b of the second separator 16. The solid seal KS1 can be bonded to the groove 34.
[0041]
Therefore, this aspect can be expressed as follows as a manufacturing method of the fuel cell stack N.
The solid polymer electrolyte membrane (for example, the solid polymer electrolyte membrane 18 in the embodiment) is replaced with the anode side diffusion electrode (for example, the anode electrode 22 and the second diffusion layer 26 in the embodiment) and the cathode side diffusion electrode (for example, in the embodiment). An electrode film structure (for example, the fuel cell 12 in the embodiment) configured to be sandwiched between the cathode electrode 20 and the first diffusion layer 24) is paired with a pair of separators (for example, one first separator 14 in the embodiment). And the other second separator 16) to form a unit fuel cell (for example, the unit fuel cell 10 in the embodiment), and a fuel cell stack (for example, implementation) configured by stacking a plurality of the unit fuel cells. In the manufacturing method of the fuel cell stack N) in the embodiment, the surface of the other separator, the surface on the electrode membrane structure side (for example, An adhesive liquid seal (for example, the liquid seal S in the embodiment) is applied to a predetermined position (for example, the groove 28 in the embodiment) of the surface 16a) in the embodiment, and the electrode film structure side of one of the surfaces of the separator is applied. An adhesive liquid seal (for example, the liquid seal S in the embodiment) is applied to a predetermined position (for example, the groove 28 in the embodiment) of a surface (for example, the surface 14a in the embodiment), and the one separator and the other separator are applied. And sandwiching the electrode film structure, the liquid seals are bonded to each other and heated to be cured, and the surface of the other separator, which is adjacent to the surface on the one separator side (for example, the surface 16b in the embodiment). In a predetermined position (for example, the groove 34 in the embodiment), one separator side surface is a non-adhesive solid seal (for example, the solid seal in the embodiment). KS1) sets, is characterized by laminating them.
[0042]
By comprising in this way, since the solid seal of the other separator and one separator laminated | stacked on this peel easily, there exists an effect which becomes easy to disassemble and reassemble. Further, since the solid seal is preliminarily molded outside, it is only necessary to set it at a predetermined position at the time of assembly, and the application process can be omitted as in the case of using a liquid seal, and the productivity can be improved.
[0043]
Therefore, also in this aspect, when the fuel cell stack N is manufactured by stacking the above units, the solid seal KS1 can be easily disassembled and reassembled, so that the unit fuel cell 10 can be easily replaced and rebuilt. Is excellent. In addition, since the solid seal KS1 only needs to be molded in advance and set in the groove 34, the application step as in the case of using a liquid seal can be omitted, and the productivity can be improved.
Since the liquid seal S which is an adhesive seal is used in the portion where the fuel cell 12 is sandwiched, this portion does not peel off during disassembly and reassembly.
In this way, a plurality of sets of the first separator 14, the fuel cell 12 and the second separator 16 stacked in the above-described manner are stacked and tightened by the first and second end plates 80 and 82, and the fuel cell stack N Is assembled.
[0044]
Here, as shown in FIG. 12 and FIG. 13, shear strength measurement was performed when two separators SP were bonded by the liquid seal SS. The measurement was performed by setting the polymerization margin in the length direction of the two separators SP to 20 mm, the polymerization margin in the width direction to 25 mm, and a tensile speed of 50 mm / min in the length direction.
The liquid sealant and separator material used are shown in Table 1. Here, as the sealing agent, the thermosetting fluorine-based sealing agent 1 and the thermosetting fluorine-based sealing agent 2 were cured at 120 ° C. for 3 hours. The thermosetting silicone sealant was cured at 120 ° C. for 1 hour. On the other hand, as the separator material, the mold carbon used was 80% carbon powder and 20% phenol resin, and the fired carbon was obtained by cutting a fired carbon plate.
[0045]
[Table 1]

[0046]
The experimental results are shown in FIG. In FIG. 14, the vertical axis represents the shear bond strength (kgf / cm 2) and the horizontal axis represents the material used. According to this experimental result, when the thermosetting fluorine-based sealant 1 is used, even if any of mold carbon, calcined carbon, SUS316 (stainless steel), AL is used as the separator material, Even when the separator was damaged when it was tested by the above-mentioned pulling speed after being applied and heated and cured, no peeling occurred at any bonding site. Similar results were obtained even when a thermosetting silicone sealant (addition reaction type) was used.
[0047]
Here, when the thermosetting silicone sealant was used, the shear bond strength to the mold carbon and sintered carbon was 2 kgf / cm 2 at the minimum. In the case of modularization, if the shear bond strength with the separator is 2 kgf / cm 2 or more, it can be determined that lamination and desorption are possible without peeling for handling. That is, the adhesive seal indicates that the shear bond strength is 2 kgf / cm 2 or more.
[0048]
On the other hand, in the thermosetting fluorine-based sealant 2, since a type having almost no adhesive functional group was used, it was actually applied to a baked carbon separator or a molded carbon separator, and the liquid seal was cured as a unit fuel cell and assembled. After that, when the separator was peeled off by hand, it was easily peeled off.
Since the shear adhesive strength of the thermosetting fluorine-based sealant 2 to each separator material is 0 to 0.5 kgf / cm 2, if it is 0.5 kgf / cm 2 or less, a failure is detected in the fuel cell stack. Even so, the defective unit battery 10 can be easily removed.
That is, the non-adhesive seal indicates that the shear adhesive strength is 0.5 kgf / cm 2 or less. Moreover, the thing of the range whose shear adhesive strength is 0.5-2 kgf / cm2 shall be included in a non-adhesive seal as a low adhesive seal.
[0049]
Here, as described above, the non-adhesive seal and the adhesive seal are determined based on the shear adhesive strength at the time of use, and are not classified according to the type of adhesive. Therefore, even if an adhesive sealing material having a shear adhesive strength of 2 kgf / cm 2 or more when the separator is adhered to the part and heat-cured after application is applied, it is left to stand for a certain period of time after application and heat-curing. Then, when the separator is used in close contact, when the shear bond strength at that portion is smaller than 2 kgf / cm 2, a non-adhesive seal (low adhesion seal) is obtained.
[0050]
According to the above embodiment, between the first separator 14 and the second separator 16, the anode electrode 22 and the second diffusion layer 26 constituting the electrode reaction surface of the fuel cell 12 via the fuel cell 12, A liquid seal S, which is an adhesive seal, is provided to prevent the reaction gas from leaking to the outer peripheral portions of the cathode electrode 20 and the first diffusion layer 24, and the surface 14 b of the adjacent first separator 14 and the second separator 16 are provided. Since the liquid seal S1 that is a non-adhesive seal or the solid seal KS1 is provided between the surface 16b, the liquid seal S1 that is a non-adhesive seal between the stacked unit fuel cells 10. The first separator 14 and the second separator 16 that are adjacent to each other can be easily separated at the portion where the coating is applied.
[0051]
Therefore, for example, when the unit fuel cell 10 has to be replaced because the first separator 14 and the second separator 16 are damaged, the above-described operation is performed between the adjacent first separator 14 and the second separator 16. Excellent rebuild performance that allows easy disassembly and reassembly. Here, since an adhesive liquid seal S is used between the first separator 14 and the second separator 16 that sandwich the fuel battery cell 12, it may cause peeling at this portion during disassembly and reassembly. There is nothing.
[0052]
In addition, the shape of the liquid seal S that is in direct contact with the protruding portion 18 a provided around the solid polymer electrolyte membrane 18 changes between the solid polymer electrolyte membrane 18 and the first and second separators 14 and 16. Therefore, it is possible to follow the variation in the seal dimensions and ensure a certain surface pressure in each groove 28, 30, 34, 35, so that there is no gap between the two, and airtightness between them can be secured. A uniform sealing reaction force can be obtained over the entire circumference between the first and second separators 14 and 16 and the fuel battery cell 12, and a uniform sealing property can be ensured.
Therefore, it is not necessary to strictly manage the dimensions of the first and second separators 14 and 16 and the fuel cell 12 particularly in the thickness direction because of the good followability with respect to the dimensional error due to the liquid seal S. It becomes easy and the cost can be reduced.
[0053]
The liquid seal S applied to the groove portions 28 of the first and second separators 14 and 16 is in close contact with the protruding portion 18a of the solid polymer electrolyte membrane 18 while maintaining a certain width in the groove portion 28. Thus, since the fuel cell 12 can be deformed according to the seal dimension, the airtightness at the seal portion can be ensured only by sandwiching the fuel cell 12 between the first and second separators 14 and 16.
[0054]
Then, the liquid seal S absorbs the variation in the seal size between the first and second separators 14 and 16 and the protruding portion 18a of the solid polymer electrolyte membrane 18, whereby a biased force is applied to the separators 14 and 16. Since the action can be prevented, the separators 14 and 16 can be thinned, and the overall weight and size can be reduced. Therefore, there is a limitation on the arrangement space, which is suitable when the separators 14 and 16 are used for vehicles that need to be made as thin as possible.
[0055]
Further, in order to make the liquid seal S adhere directly to the solid polymer electrolyte membrane 18, for example, the number of parts and the number of assembling steps are reduced as compared with a case where a frame-like frame is provided around the fuel electric cell 12. This is advantageous in that it can be reduced. Further, the surface pressure of the liquid seal S against the solid polymer electrolyte membrane 18 becomes uniform, and the solid polymer electrolyte membrane 18 does not receive a biased force. Even when the solid polymer electrolyte membrane 18 undulates, the solid polymer electrolyte membrane 18 can be deformed accordingly, so that the solid polymer electrolyte membrane 18 does not wrinkle.
[0056]
【The invention's effect】
As described above, according to the first aspect of the present invention, the non-adhesive seal is used between the adjacent separators between the stacked unit fuel cells. Since both separators can be separated, for example, after assembling the fuel cell stack, even when it is desired to replace the unit fuel cell, the corresponding unit fuel cell can be easily removed, and the rebuild performance is excellent. There is an effect that. Further, when removing the unit fuel cell in this way, since an adhesive seal is used between the pair of separators, there is no separation between the electrode membrane structure and there is no problem. No peeling occurs between each diffusion electrode and the separator.
[Brief description of the drawings]
FIG. 1 is an overall assembly view of an embodiment of the present invention.
FIG. 2 is an exploded perspective view of a main part of an embodiment of the present invention.
3 is a cross-sectional view taken along a line AA in FIG.
FIG. 4 is a view of the first separator according to the embodiment of the present invention as seen in the direction of arrow B in FIG.
FIG. 5 is a view of the second separator according to the embodiment of the present invention as viewed in the direction of arrow C in FIG.
6 is a view of the second separator according to the embodiment of the present invention as seen from the direction of arrow D in FIG.
7 is a partially enlarged view of FIG. 3 according to the embodiment of the present invention.
FIG. 8 is an explanatory diagram showing a first aspect of a stacking procedure according to an embodiment of the present invention.
FIG. 9 is an explanatory diagram showing a second aspect of the stacking procedure according to the embodiment of the present invention.
FIG. 10 is an explanatory diagram showing a third aspect of the stacking procedure according to the embodiment of the present invention.
FIG. 11 is an explanatory diagram showing a fourth aspect of the stacking procedure according to the embodiment of the present invention.
FIG. 12 is an explanatory side view showing an experimental situation.
13 is a view on arrow X in FIG. 12;
FIG. 14 is a graph showing experimental results.
FIG. 15 is a cross-sectional view of the prior art.
[Explanation of symbols]
10 unit fuel cell
12 Fuel cell (electrode membrane structure)
14 First separator
16 Second separator
18 Solid polymer electrolyte membrane
20 Cathode electrode
22 Anode electrode
24 First gas diffusion layer
26 Second gas diffusion layer
N Fuel cell stack
S Liquid seal (adhesive seal)
S1 Liquid seal (non-adhesive seal)

Claims (3)

A unit fuel cell is formed by sandwiching an electrode membrane structure formed by sandwiching a solid polymer electrolyte membrane between an anode side diffusion electrode and a cathode side diffusion electrode with a pair of separators, and a plurality of unit fuel cells are formed. In the fuel cell stack configured by stacking, in order to prevent leakage of the reaction gas from the electrode reaction surface of the electrode membrane structure to the outer peripheral portion of the anode side diffusion electrode or the cathode side diffusion electrode between the pair of separators The fuel cell stack is characterized in that an adhesive seal is provided on each of the adjacent unit fuel cells, and a non-adhesive seal is provided between adjacent separators of adjacent unit fuel cells to facilitate replacement work for each unit fuel cell .   2. The fuel cell stack according to claim 1, wherein the non-adhesive seal is obtained by press-bonding the adhesive seal and heating and curing the adhesive seal.   2. The method of manufacturing a fuel cell stack according to claim 1, wherein the non-adhesive seal is manufactured by press-bonding the adhesive seal and heating and curing. 3. Method.

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