200805770 (1) 九、發明說明 【發明所屬之技術領域】 本發明係有關燃料電池。 【先前技術】 近年來，個人電腦、手機等各種電子機器隨著半導體 技術之發達呈小型化。嘗試將燃料電池用於此等小型機器 用之電源。燃料電池可僅供燃料與氧化劑進行發電，連續 補充、更換燃料即可發電之優點存在。因此，使燃料電池 儘可能小型化即可極有利於攜帶電子機器運作之系統。特 別是’直接甲醇型燃料電池（DMFC ; direct methanol fuel cell )係使㈣量密度局之甲醇用於燃料，於電極觸媒上直 接由甲醇取出電流，因而可呈小型化，相較於燃料之使用 亦比氫氣燃料容易，極可期待爲小型機器用電源。 做爲DMFC之燃料供應方法者，以吹燃器等使液體燃 料氣化後送入燃料電池內之氣體供應型DMFC與直接以泵 等將液體燃料送入燃料電池內之液體供應型DMFC等。惟 ’此等燃料供應方法中，欲進行上述之供給甲醇之泵、送 入空氣之吹入器均務必補助器，不僅系統形態複雜之外， 欲呈小型化亦極爲不易之缺點存在。 另外’如專利公報第3 4 i 3丨丨丨號所示之內部氣化型 DMFC爲另一種公知的燃料供給方法。此內部氣化型 DMFC具備有保持液體燃料之燃料滲透層與爲使保持於燃 料滲透層中之液體燃料中氣化成份之擴散的燃料氣化層。 -5- (2) 200805770 又，此內部氣化型DMFC中，所氣化之液體燃料由燃料氣 化層供入陽極。專利公報第3 4 1 3 1 1 1號中，使用液體燃料 之甲醇與水以1 : 1之莫耳比所混合之甲醇水溶液，使甲 醇與水兩者以氣化氣體之形態供應於陽極。 藉由此專利公報所示之內部氣化型DMFC後，無法有 效取得高度輸出功率之特性。相較於甲醇，其水之蒸氣壓 較低，水的氣化速度比甲醇之氣化速度慢，因此，甲醇、 或水藉由氣化供入陽極後，對於甲醇供給量水的供給量相 對不足。其結果，使甲醇進行內部改質反應之反應電阻變 高，因此，無法有效取得充份的輸出功率特性。 【發明內容】 本發明目的係提供一種改善輸出功率密度之燃料電池 〇 本發明之燃料電池其特徵係具備陰極與陽極，與配置 於該陰極與陽極間，對於水穿透値而言，甲醇穿透値之比 爲〇 . 5以下之固體電解質膜，與收容含有甲醇之液體燃料 之燃料室，以及至少供應該液體燃料之蒸氣於該陽極之供 應手段。 又，本發明之燃料電池之特徵係具備陰極與陽極，與 配置於該陰極與該陽極間，對於水穿透値而言，甲醇穿透 値之比爲0.5以下之固體電解質膜，與收容含有甲醇之液 體燃料之燃料室，與使配置於該燃料室與該陽極間之該燃 料室之該液體燃料之蒸氣以選擇性透過之氣液分離層。 -6 - (3) (3)200805770 【實施方式】 [發明實施之最佳形態] 本發明者進行精密硏討後結果發現，使液體燃料之蒸 氣供應於陽極之燃料電池中，對於固體電解質膜之水穿透 値而言，其甲醇穿透値之比（以下稱穿透比）爲〇. 5以下 時，可取得高輸出功率密度。當穿透比超出〇. 5則由陰極 往陽極之水擴散少，改質反應之反應電阻高，將無法取得 高輸出功率密度。穿透比愈小，對於陽極的水供應量增加 ，相反的，降低甲醇擴散性，而降低發電初期之輸出功率 。因此，發電初期陰極之水生成量少，而由陰極往陽極擴 散之水量少。因此，爲不使穿透比過度下降，於陰極供應 甲醇後藉由甲醇氧化反應後可生成水，同時所生成之水通 過固體電解質膜後可於陽極擴散，因此可補充發電初期之 水不足，可由發電初期取得高輸出功率。 又，使液體燃料供應於陽極之送液型燃料電池中，使 用穿透比爲0.5以下之水透過性高的固體電解質膜後，陰 極中氣體擴散性降低，供於陽極之燃料藉由稀釋等降低輸 出功率密度。送液型燃料電池中，甲醇穿透値與水穿透値 以幾乎相互爲接近〇之固體電解質膜者宜。大多使用之 Nafion®膜做成之固體電解質膜其穿透比超出0.5。 穿透比之測定依以下說明之方法進行。首先，如圖1 所示，於Η型電池21中裝置固體電解質膜22。Η型電池 21係具備於外圍面分別具有連接管23a、23b之2根圓筒 (4) (4)200805770 管24a、2 4b。於圓筒管24a之連接管23a與圓筒管24b之 連接管23b之間配置固體電解質膜22，將固體電解質膜 2 2之上端與連接管2 3 a、2 3b之頂端以挾持構件2 5挾住’ 固體電解質膜22之下端與連接管23a、23b之頂端以挾持 構件25挾住。做爲挾持構件25之例如：螺絲、彈簧、等 例。於右側之圓筒管24a收容純甲醇，於左側之圓筒管 2 4b收容與其同量之水。使純甲醇與水的溫度保持25 °C， 每隔1小時至6小時爲止將圓筒管24a、24b分別之液體 進行採樣，進行各液體之水與甲醇濃度分析。針對右側圓 筒管24a於每1小時測定取得之水濃度進行平均化。左 側圓筒管24b於每1小時測定取得之甲醇濃度進行平均 化。將平均水濃度做爲水的穿透値，平均甲醇濃度做爲甲 醇穿透値。 固體電解質膜之甲醇穿透値以1 μΜ/cm2 · s以下爲佳 。若甲醇穿透値超出1 μΜ/cm2 · s則甲醇穿透將會造成燃 料消耗量之增加，恐將無法取得高輸出功率密度。含於固 體電解質膜之質子傳導性物質中可使用如：烴系樹脂。 做爲液體燃料者如：純甲醇、甲醇水溶液等例。液體 燃料之甲醇濃度以64重量％以上、1〇〇重量％以下爲宜 。穿透比爲〇 . 5以下之固體電解質膜具良好的水擴散性， 因此，液體燃料之甲醇濃度低時，水透過固體電解質膜後 供於陰極，導致陰極之氣體擴散性降低等，恐將降低輸出 功率密度。更理想之甲醇濃度範圍爲65重量％以上、1〇〇 重量％以下。 (5) 200805770 以下’參考圖面進行說明本發明燃料電池實施形態之 一的直接甲醇型燃料電池。 圖2係代表本發明實施形態之直接甲醇型燃料電池之 模式截面圖。 如圖2所示之膜電極連接體（MEA) i係具備由陰極 觸媒層2及陽極氣體擴散層4所成之陰極（如：氧化劑極 )、與由陽極觸媒層3及陽極氣體擴散層5所成之陽極（ 如：燃料極）、與配置於陰極觸媒層2與陽極觸媒層3之 間的固體電解質膜6。 做爲含於陰極觸媒層2及陽極觸媒層3之觸媒例者如 :鉑族元素之單體金屬（Pt、Ru、Rh、Ir、Os、Pd等）， 含鈾族兀素之合金等例。陽極觸媒中以使用對於甲醇、氧 化碳之耐性強的Pt-Ru，陰極觸媒中以使用鉑者宜，惟， 並未受限於此。又，使用利用碳材料類之導電性載體之擔 載觸媒，或使用無擔載觸媒均可。 陰極觸媒層2係層合於陰極氣體擴散層4上，且陽極 觸媒層3係層合於陽極氣體擴散層5上。陰極氣體擴散層 4係擔任使氧化劑均勻供於陰極觸媒層2之角色，而亦兼 任陰極觸媒層2之集電體。另外，陽極氣體擴散層5係擔 任使燃料均勻供於陽極觸媒層3之角色，同時亦兼任陽極 觸媒層3之集電體。陰極導電層7a及陰極導電層7b分別 與陰極氣體擴散層4及陽極氣體擴散層5相連接。陰極導 電層7a與陽極導電層7b中分別可使用由金等金屬材料所 成之多孔質層（如：網篩）。 -9- (6) (6)200805770 矩形框狀之陰極密封材料8a係位於陰極導電層7a與 固體電解質膜6之間，同時環繞陰極觸媒層2及陰極氣體 擴散層4之周圍。另外，矩形框狀之陽極密封材料8b係 位於陽極導電層7b與固體電解質膜6之間，同時環繞陽 極觸媒層3及陽極氣體擴散層5之周圍。陰極密封材料8 a 及陽極密封材料8b係爲防止由膜電極連接體1之燃料之 洩漏及氧化劑之洩漏之Ο型環。 膜電極連接體1之下方配置有燃料室之液體燃料池9 。液體燃料池9內收容有液體之甲醇或甲醇水溶液。 做爲氣液分離層之氣液分離膜1 0係選擇性透過液體 燃料之蒸氣，具有使液體燃料之蒸氣與液體成份分離之功 能。做爲氣液分離膜1 0之例者如：聚矽氧橡膠薄片之例 ，氣液分離膜1 0係配置於液體燃料池9之開口端。 氣液分離膜1 〇與陽極導電層7b之間層合樹脂製之框 體1 1。框體1 1所圍繞之空間係暫時收容擴散氣液分離膜 1 〇之蒸氣做爲蒸氣收容室1 2 (亦即蒸氣聚集）之功能。 藉由此蒸氣收容室1 2及氣液分離膜1 0之透過甲醇量抑制 效果後，可避免一次大量蒸氣供與陽極觸媒層3，可抑制 甲醇穿透的產生。另外，框體1 1爲矩形之框體，如由 PET類之熱塑性聚酯樹脂所形成。 於陰極導電層7 a上層合保濕板1 3。保濕板1 3係擔任 抑制陰極觸媒層2中所生成之水的蒸散角色，同時亦擔任 於陰極氣體擴散層4中均勻導入氧化劑後，促進氧化劑均 勻擴散於陰極觸媒層2之補助擴散層之角色。 -10 - (7) 200805770 爲攝取氧化劑空氣之空氣導入口 1 4所形成複數個外 罩1 5係層合於保濕板1 3。外罩1 5係擔任使含膜電極連接 體1之排氣管進行加壓後提高其密合性之角色，如：由 SUS 3 04類之金屬所形成。 如上述構成之直接甲醇型燃料電池，其液體燃料池9 內之液體燃料氣化後，液體燃料之蒸氣使氣液分離膜i 〇 擴散後’暫時收容於蒸氣收容室1 2，由其緩緩使陽極氣體 擴散層5擴散後，供應於陽極觸媒層3。又，部份蒸氣通 過固體電解質膜6後，亦供於陰極。此等結果產生以下反 應式（1 )所示之甲醇內部改質反應。 CH3OH + H2OC〇2 + 6H + + 6e (1) 於內部改質反應所生成之質子（H+)係使固體電解質 膜6擴散後到達陰極觸媒層3。另外，由外罩1 5之空氣導 入口 1 4所攝取之空氣使保濕板1 3及陰極氣體擴散層4擴 散後供於陰極觸媒層2。陰極觸媒層2中，藉由下述（2 ) 式所示之反應後生成水，亦即產生發電反應。 (3/2) 02 + 6H + + 6e--> 3H20 (2) 進行發電反應後，藉由前述（2)式之反應等於陰極 觸媒層2中生成水，而使陰極氣體擴散層4內擴散後到達 保濕板1 3，藉由保濕板1 3阻礙蒸散，增加陰極觸媒層2 中之水份貯存量。另外，於陽極側通過氣液分離膜1 0後 ，供應水蒸氣，或完全未供應狀態。因此，伴隨發電反應 之進行，可作出陰極觸媒層2之水份保持量多於陽極觸媒 層3之水份保持量之狀態。 -11 - (8) 200805770 固體電解質膜6之穿透比爲0.5以下，因此可促進由 陰極觸媒層2往陽極觸媒層3之水的擴散，促進如上述（ 1 )式所示之甲醇內部改質反應，藉此可取得高輸出功率 密度。 又，於上述實施形態中具有保濕板1 3，而本發明具備 保濕板之構成並未受限。藉由穿透比爲0 · 5以下之固體電 解質膜後，即使未具有保濕板1 3仍可促進由陰極往陽極 之水擴散，可取得高輸出功率密度。 以下，參考圖面詳細說明本發明。 (實施例1〜實施例5 ) <陽極之製作> 於陽極用觸媒（Pt : Ru=l : 1)擔載碳黑中添加全 氟碳磺酸溶液與水及甲氧基丙醇，使該觸媒擔載碳黑進行 分散後，調製糊料。將取得糊料塗佈於陰極氣體擴散層之 多孔質碳紙後取得厚度4 5 0 μπι之陽極。 <陰極之製作> 於陰極用觸媒（Pt )擔載碳黑上添加全氟碳磺酸溶液 與水及甲氧基丙醇，使該觸媒擔載碳黑進行分散後，調製 糊料。將取得糊料塗佈於陰極氣體擴散層之多孔質碳紙後 ’取得厚度400μιη之陰極。 <固體電解質膜之製作> -12- (9) 200805770 以上述圖1所示之方法測定具有各種穿透比之固體電 解質膜之穿透比。穿透比如下述表1所示。 於陽極觸媒層與陰極觸媒層之間配置固體電解質膜， 此等藉由熱壓延後，取得膜電極連接體（MEA )。 準備保濕板之厚度爲5 00μιη，透氣度爲2秒/100cm3 (JIS P-8117)、透濕度爲 4000g/m2 24h ( JIS L- 1 099 A-1 法）之聚苯乙烯製多孔質薄膜。 框體係PET製、厚度25 μιη者。另外準備氣液分離膜 爲厚度200 μιη之聚矽氧橡膠薄片。 使用所得膜電極連接體、保濕板、框體、氣液分離膜 後組裝具前述圖2所示之構造的內部氣化型直接甲醇型燃 料電池。此時，燃料電池中收容2mL之純度99.9重量％ 之純甲醇。 (比較例1〜3 ) 除使用具有本發明所規定之穿透比範圍外之穿透比之 膜爲固體電解質膜之外，組裝與前述實施例1所說明者相 同之構成之內部氣化型之直接甲醇型燃料電池。 -13 - (10) 200805770 [表i] 穿透比 實 施 例 1 0· 5 實 施 例 2 0. 4 實 施 例 3 0.3 實 施 例 4 0. 2 實 施 例 5 0.1 比 較 例 1 1 比 較 例 2 0.9 比 較 例 3 0.7 針對取得燃料電池，測定增加電流密度（mA/cm2)時 之輸出功率密度變化結果，具穿透比爲0.5以下之固體電 解質膜之實施例1〜5之燃料電池可取得高輸出功率密度。 相較於此，具有穿透比爲超出0.5之固體電解質膜之 比較例1〜3之燃料電池其輸出功率密度則低於實施例1〜5 〇 另外’本發明並未受限於上述實施形態，於實施階段 ，只要不跳脫其主旨範圍下，可具體化變更構成要素。又 ’藉由適S組合上述實施形態所揭示之複數構成要素後， 可形成各種發明。如：亦可由實施形態所示之構成要素去 除幾個構成要素。更可進一步適當組合不同實施形態之構 成要素。 如：上述說中做爲燃料電池之構成者，於膜電極連 接體（MEA )之下部設置燃料貯存部（燃料室），至少於 陽極丨共^ ff ί然#胃氣之供給手段以使用氣液分離層之構 η進行説明’而由燃料收容部（燃料室）往μΕΑ之燃料 一 14- (11) 200805770 供給係將流路配置於燃料室與MEA之間，經由此流路供 與液體燃料與液體燃料蒸氣後進行亦可。又，做爲燃料電 池本體之構成者以被動型之燃料電池舉例說明，而對於於 燃料供給等部份使用泵等之半被動型之燃料電池亦可適用 本發明。陽極中亦可供應液體燃料蒸氣，而將液體燃料蒸 氣與液體燃料供於陽極時，仍可適用本發明。即使此等構 成仍可取得與上述說明相同之作用效果。 [產業上可利用性] 本發明可提供改善輸出功率密度之燃料電池。 【圖式簡單說明】 [圖1 ] 圖1係代表對於水穿透値而言，進行測定甲 醇穿透値之比時所使用裝置之模式圖。 [圖2] 圖2係代表本發明實施形態之一的直接甲醇 型燃料電池之模式截面圖。 【主要元件符號說明】 1 :膜電極連接體 2 :陰極觸媒層 3 :陽極觸媒層 4 :陰極氣體擴散層 5 :陽極氣體擴散層 6 :固體電解質膜 -15- (12) (12)200805770 7a :陰極導電層 7b :陽極導電層 8a :陰極密封材料 8b :陽極密封材料 9 :液體燃料池 I 〇 :氣液分離膜 II :框體 1 2 :蒸氣收容室 13 :保濕板 1 4 :空氣導入口 1 5 :外罩 21 : Η型電池 22 :固體電解質膜 23a、 23b ：連接管 24a 、 24b :圓筒管 25 :挾持構件 -16-200805770 (1) Description of the Invention [Technical Field of the Invention] The present invention relates to a fuel cell. [Prior Art] In recent years, various electronic devices such as personal computers and mobile phones have been miniaturized with the development of semiconductor technology. Try using a fuel cell for the power supply of these small machines. The fuel cell can be used only for fuel and oxidant to generate electricity, and the advantages of continuously replenishing and replacing fuel can generate electricity. Therefore, making the fuel cell as small as possible can be extremely advantageous for a system that carries an electronic machine. In particular, the direct methanol fuel cell (DMFC) uses (4) the mass density of methanol for the fuel, and the current is directly extracted from the methanol on the electrode catalyst, so that it can be miniaturized compared to the fuel. It is also easier to use than hydrogen fuel, and it is expected to be a power source for small machines. As a fuel supply method of the DMFC, a gas supply type DMFC that vaporizes the liquid fuel by a gas burner or the like, and a liquid supply type DMFC that directly feeds the liquid fuel into the fuel cell by a pump or the like is used. However, in the fuel supply method, it is necessary to perform the above-described pump for supplying methanol and the blower for supplying air, and the auxiliary device is not only complicated in form but also extremely difficult to be miniaturized. Further, the internal vaporization type DMFC shown in the Japanese Patent Publication No. 3 4 i 3 No. is another known fuel supply method. The internal gasification type DMFC is provided with a fuel gasification layer for maintaining a fuel permeation layer of a liquid fuel and for diffusing a gasification component in a liquid fuel held in the fuel permeation layer. -5- (2) 200805770 Further, in this internal gasification type DMFC, the vaporized liquid fuel is supplied to the anode from the fuel vaporization layer. In the patent publication No. 3 4 1 3 1 1 1 , a methanol aqueous solution in which a liquid fuel of methanol and water are mixed at a molar ratio of 1:1 is used, and both methanol and water are supplied to the anode in the form of a gasification gas. With the internal vaporization type DMFC shown in this patent publication, the characteristics of high output power cannot be effectively obtained. Compared with methanol, the vapor pressure of water is lower, and the gasification rate of water is slower than that of methanol. Therefore, after methanol or water is supplied to the anode by gasification, the supply amount of water to methanol is relatively insufficient. As a result, the reaction resistance for the internal reforming reaction of methanol is increased, so that sufficient output characteristics cannot be obtained efficiently. SUMMARY OF THE INVENTION The object of the present invention is to provide a fuel cell with improved output power density. The fuel cell of the present invention is characterized in that it has a cathode and an anode, and is disposed between the cathode and the anode. The solid electrolyte membrane having a ratio of 値. 5 or less, a fuel chamber containing a liquid fuel containing methanol, and a supply means for supplying at least a vapor of the liquid fuel to the anode. Further, the fuel cell of the present invention is characterized in that a cathode and an anode are provided, and a solid electrolyte membrane having a methanol permeation ratio of 0.5 or less is disposed between the cathode and the anode, and the water permeation crucible is 0.5 or less. a fuel chamber of the liquid fuel of methanol and a gas-liquid separation layer for selectively permeating the vapor of the liquid fuel disposed in the fuel chamber between the fuel chamber and the anode. -6 - (3) (3) 200805770 [Embodiment] [Best Mode for Carrying Out the Invention] The inventors of the present invention have found that the vapor of the liquid fuel is supplied to the fuel cell of the anode for the solid electrolyte membrane. When the water penetrates the crucible, the ratio of the methanol permeation enthalpy (hereinafter referred to as the penetration ratio) is 〇. 5 or less, and a high output power density can be obtained. When the penetration ratio exceeds 〇. 5, the water from the cathode to the anode is less diffused, and the reaction resistance of the reforming reaction is high, so that high output power density cannot be obtained. The smaller the penetration ratio, the greater the water supply to the anode, and conversely, the lower the methanol diffusivity, and the lower the initial output of the power generation. Therefore, the amount of water generated by the cathode at the initial stage of power generation is small, and the amount of water diffused from the cathode to the anode is small. Therefore, in order to prevent the breakthrough ratio from being excessively lowered, water can be generated by the methanol oxidation reaction after the methanol is supplied to the cathode, and the generated water can be diffused at the anode after passing through the solid electrolyte membrane, thereby supplementing the water shortage at the initial stage of power generation. High output power is achieved at the beginning of power generation. Further, in the liquid-feeding type fuel cell in which the liquid fuel is supplied to the anode, the solid electrolyte membrane having a water permeability of 0.5 or less is used, and the gas diffusibility in the cathode is lowered, and the fuel supplied to the anode is diluted or the like. Reduce output power density. In a liquid-feeding type fuel cell, it is preferable that methanol penetrates 値 and water penetrates 固体 to a solid electrolyte membrane which is close to each other. A solid electrolyte membrane made of a Nafion® membrane, which is mostly used, has a penetration ratio exceeding 0.5. The penetration ratio was determined by the method described below. First, as shown in FIG. 1, the solid electrolyte membrane 22 is placed in the Η-type battery 21. The Η-type battery 21 includes two cylinders (4) (4) 200805770 tubes 24a and 24b each having a connection pipe 23a, 23b on the outer peripheral surface. A solid electrolyte membrane 22 is disposed between the connecting tube 23a of the cylindrical tube 24a and the connecting tube 23b of the cylindrical tube 24b, and the upper end of the solid electrolyte membrane 2 2 and the top end of the connecting tubes 2 3 a and 2 3b are held by the holding member 25 The lower end of the solid electrolyte membrane 22 and the tips of the connecting tubes 23a, 23b are caught by the holding member 25. As the holding member 25, for example, a screw, a spring, and the like. The cylindrical tube 24a on the right side contains pure methanol, and the cylindrical tube 24b on the left side accommodates the same amount of water. The temperature of the pure methanol and water was maintained at 25 ° C, and the liquids of the cylindrical tubes 24a and 24b were sampled every 1 hour to 6 hours, and the water and methanol concentrations of the respective liquids were analyzed. The water concentration obtained by measuring the measurement of the right circular bobbin 24a per hour was averaged. The left cylindrical tube 24b was averaged by measuring the methanol concentration obtained every one hour. The average water concentration was taken as the breakthrough enthalpy of water, and the average methanol concentration was taken as methanol penetration enthalpy. The methanol penetrating enthalpy of the solid electrolyte membrane is preferably 1 μΜ/cm 2 · s or less. If the methanol breakthrough 値 exceeds 1 μΜ/cm2 · s, methanol penetration will cause an increase in fuel consumption, and it is feared that high output power density will not be achieved. For example, a hydrocarbon resin can be used for the proton conductive material contained in the solid electrolyte membrane. As a liquid fuel, such as: pure methanol, aqueous methanol solution and the like. The methanol concentration of the liquid fuel is preferably 64% by weight or more and 1% by weight or less. The solid electrolyte membrane having a penetration ratio of 〇. 5 or less has good water diffusibility. Therefore, when the methanol concentration of the liquid fuel is low, water is supplied to the cathode after passing through the solid electrolyte membrane, resulting in a decrease in gas diffusibility of the cathode, etc. Reduce output power density. More preferably, the methanol concentration is in the range of 65% by weight or more and 1% by weight or less. (5) 200805770 A direct methanol fuel cell of one embodiment of the fuel cell of the present invention will be described below with reference to the drawings. Fig. 2 is a schematic cross-sectional view showing a direct methanol fuel cell according to an embodiment of the present invention. The membrane electrode assembly (MEA) i shown in FIG. 2 includes a cathode (eg, an oxidant electrode) formed by the cathode catalyst layer 2 and the anode gas diffusion layer 4, and diffused from the anode catalyst layer 3 and the anode gas. An anode (e.g., a fuel electrode) formed in the layer 5 and a solid electrolyte membrane 6 disposed between the cathode catalyst layer 2 and the anode catalyst layer 3. As a catalyst for the cathode catalyst layer 2 and the anode catalyst layer 3, for example, a platinum group element monomer metal (Pt, Ru, Rh, Ir, Os, Pd, etc.), containing uranium group Alloys and other examples. In the anode catalyst, Pt-Ru which is highly resistant to methanol or carbon oxide is used, and platinum is preferably used in the cathode catalyst, but it is not limited thereto. Further, either a supported catalyst using a conductive material of a carbon material or an unsupported catalyst may be used. The cathode catalyst layer 2 is laminated on the cathode gas diffusion layer 4, and the anode catalyst layer 3 is laminated on the anode gas diffusion layer 5. The cathode gas diffusion layer 4 serves as a current collector for uniformly supplying the oxidant to the cathode catalyst layer 2, and also serving as the cathode catalyst layer 2. Further, the anode gas diffusion layer 5 serves as a current collector for uniformly supplying the fuel to the anode catalyst layer 3 and also serving as the anode catalyst layer 3. The cathode conductive layer 7a and the cathode conductive layer 7b are connected to the cathode gas diffusion layer 4 and the anode gas diffusion layer 5, respectively. A porous layer (e.g., mesh) made of a metal material such as gold may be used for each of the cathode conductive layer 7a and the anode conductive layer 7b. -9- (6) (6) 200805770 A rectangular frame-shaped cathode sealing material 8a is disposed between the cathode conductive layer 7a and the solid electrolyte membrane 6 while surrounding the cathode catalyst layer 2 and the cathode gas diffusion layer 4. Further, a rectangular frame-shaped anode sealing material 8b is interposed between the anode conductive layer 7b and the solid electrolyte membrane 6, while surrounding the periphery of the anode catalyst layer 3 and the anode gas diffusion layer 5. The cathode sealing material 8a and the anode sealing material 8b are Ο-type rings that prevent leakage of fuel from the membrane electrode assembly 1 and leakage of oxidant. A liquid fuel pool 9 of a fuel chamber is disposed below the membrane electrode assembly 1. The liquid fuel pool 9 contains a liquid methanol or methanol aqueous solution. The gas-liquid separation membrane 10 as a gas-liquid separation layer selectively permeates the vapor of the liquid fuel, and has a function of separating the vapor of the liquid fuel from the liquid component. As an example of the gas-liquid separation membrane 10, for example, a polysiloxane rubber sheet, the gas-liquid separation membrane 10 is disposed at the open end of the liquid fuel pool 9. A frame 11 made of a resin is laminated between the gas-liquid separation membrane 1 and the anode conductive layer 7b. The space surrounded by the frame 1 1 temporarily accommodates the function of the diffusion gas-liquid separation membrane 1 as a vapor storage chamber 1 2 (that is, vapor accumulation). By the effect of suppressing the amount of methanol permeated by the vapor storage chamber 12 and the gas-liquid separation membrane 10, it is possible to prevent a large amount of vapor from being supplied to the anode catalyst layer 3 at a time, and it is possible to suppress the occurrence of methanol permeation. Further, the frame body 1 is a rectangular frame body formed of a thermoplastic polyester resin of PET type. The moisturizing plate 13 is laminated on the cathode conductive layer 7a. The moisturizing plate 13 serves to suppress the evapotranspiration of the water generated in the cathode catalyst layer 2, and also serves as a supplementary diffusion layer for promoting uniform diffusion of the oxidizing agent to the cathode catalyst layer 2 after uniformly introducing the oxidizing agent into the cathode gas diffusion layer 4. The role. -10 - (7) 200805770 The air inlet port for ingesting oxidant air 1 4 is formed by laminating a plurality of outer covers 1 5 to the moisturizing plate 13 . The cover 15 serves to pressurize the exhaust pipe of the membrane-containing electrode connector 1 to improve the adhesion, and is formed of a metal such as SUS 3 04. In the direct methanol fuel cell configured as described above, after the liquid fuel in the liquid fuel pool 9 is vaporized, the vapor of the liquid fuel diffuses the gas-liquid separation membrane i ' and is temporarily contained in the vapor storage chamber 12, which is gradually slowed down. After the anode gas diffusion layer 5 is diffused, it is supplied to the anode catalyst layer 3. Further, a part of the vapor passes through the solid electrolyte membrane 6, and is also supplied to the cathode. These results produced the methanol internal reforming reaction represented by the following reaction formula (1). CH3OH + H2OC〇2 + 6H + + 6e (1) The proton (H+) generated by the internal reforming reaction diffuses the solid electrolyte membrane 6 and reaches the cathode catalyst layer 3. Further, the air taken in by the air introduction port 14 of the outer cover 15 diffuses the moisturizing plate 13 and the cathode gas diffusion layer 4 and then supplies it to the cathode catalyst layer 2. In the cathode catalyst layer 2, water is generated by the reaction shown by the following formula (2), that is, a power generation reaction is generated. (3/2) 02 + 6H + + 6e--> 3H20 (2) After the power generation reaction, the cathode gas diffusion layer 4 is made by the reaction of the above formula (2) being equal to the water formed in the cathode catalyst layer 2. After the inner diffusion reaches the moisturizing plate 13 and the eutectic is inhibited by the moisturizing plate 13, the amount of water stored in the cathode catalyst layer 2 is increased. Further, after passing through the gas-liquid separation membrane 10 on the anode side, water vapor is supplied, or it is not supplied at all. Therefore, with the progress of the power generation reaction, the state in which the amount of moisture retained by the cathode catalyst layer 2 is larger than the amount of moisture retained by the anode catalyst layer 3 can be made. -11 - (8) 200805770 The solid electrolyte membrane 6 has a penetration ratio of 0.5 or less, thereby promoting the diffusion of water from the cathode catalyst layer 2 to the anode catalyst layer 3, and promoting the methanol as shown in the above formula (1). Internal reforming reaction, whereby high output power density can be achieved. Further, in the above embodiment, the moisturizing plate 13 is provided, and the configuration of the present invention having the moisturizing plate is not limited. By the solid electrolyte membrane having a penetration ratio of 0.5 or less, the water diffusion from the cathode to the anode can be promoted even without the moisturizing plate 13, and a high output power density can be obtained. Hereinafter, the present invention will be described in detail with reference to the drawings. (Examples 1 to 5) <Production of Anode> A perfluorocarbonsulfonic acid solution and water and methoxypropanol were added to a carbon black supported on an anode catalyst (Pt: Ru = 1 : 1). After the catalyst is loaded with carbon black, the paste is prepared. The paste was applied to the porous carbon paper of the cathode gas diffusion layer to obtain an anode having a thickness of 450 μm. <Production of Cathode> A perfluorocarbonsulfonic acid solution, water, and methoxypropanol are added to a cathode catalyst (Pt)-supporting carbon black, and the catalyst-supported carbon black is dispersed to prepare a paste. material. The paste was applied to the porous carbon paper of the cathode gas diffusion layer to obtain a cathode having a thickness of 400 μm. <Production of Solid Electrolyte Membrane> -12- (9) 200805770 The penetration ratio of the solid electrolyte membrane having various penetration ratios was measured by the method shown in Fig. 1 described above. Penetration is shown in Table 1 below. A solid electrolyte membrane is disposed between the anode catalyst layer and the cathode catalyst layer, and the membrane electrode assembly (MEA) is obtained by hot rolling. A polystyrene porous film having a thickness of 500 Å η, a gas permeability of 2 sec/100 cm3 (JIS P-8117), and a moisture permeability of 4000 g/m 2 24h (JIS L- 1 099 A-1 method) was prepared. The frame system is made of PET and has a thickness of 25 μm. Further, the gas-liquid separation membrane was prepared to be a polyoxyethylene rubber sheet having a thickness of 200 μm. The internal vaporized direct methanol type fuel cell having the structure shown in Fig. 2 described above was assembled using the obtained membrane electrode assembly, moisturizing plate, frame, and gas-liquid separation membrane. At this time, 2 mL of pure methanol having a purity of 99.9% by weight was contained in the fuel cell. (Comparative Examples 1 to 3) The internal vaporization type of the same configuration as that described in the above Example 1 was used except that the film having the penetration ratio outside the range of the penetration ratio specified by the present invention was used as the solid electrolyte membrane. Direct methanol fuel cell. -13 - (10) 200805770 [Table i] Penetration ratio Example 1 0· 5 Example 2 0. 4 Example 3 0.3 Example 4 0. 2 Example 5 0.1 Comparative Example 1 1 Comparative Example 2 0.9 Comparative Example 3 0.7 For the fuel cell, the output power density change at the time of increasing the current density (mA/cm2) was measured, and the fuel cell of Examples 1 to 5 having a solid electrolyte membrane having a breakthrough ratio of 0.5 or less was able to achieve high output power density. . In contrast, the fuel cell of Comparative Examples 1 to 3 having a solid electrolyte membrane having a breakthrough ratio of more than 0.5 has an output power density lower than that of Examples 1 to 5, and the present invention is not limited to the above embodiment. In the implementation stage, as long as the scope of the subject matter is not removed, the components of the change can be embodied. Further, various inventions can be formed by combining the plurality of constituent elements disclosed in the above embodiments. For example, several constituent elements may be removed by the constituent elements shown in the embodiment. Further, the constituent elements of the different embodiments can be further combined as appropriate. For example, in the above description, as a constituent of the fuel cell, a fuel storage portion (fuel chamber) is disposed under the membrane electrode connector (MEA), and at least the anode is supplied with a gas supply means to use the gas. The structure η of the liquid separation layer is described as 'the fuel accommodating portion (fuel chamber) to the fuel 14 14-(11) 200805770. The supply system arranges the flow path between the fuel chamber and the MEA, and supplies the liquid through the flow path. It is also possible to carry out the fuel and liquid fuel vapor. Further, as a constituent of the fuel cell body, a passive fuel cell is exemplified, and the present invention is also applicable to a semi-passive fuel cell using a pump or the like for a fuel supply or the like. The liquid fuel vapor may also be supplied to the anode, and the present invention is still applicable when the liquid fuel vapor and the liquid fuel are supplied to the anode. Even in such a configuration, the same effects as those described above can be obtained. [Industrial Applicability] The present invention can provide a fuel cell with improved output power density. BRIEF DESCRIPTION OF THE DRAWINGS [Fig. 1] Fig. 1 is a schematic view showing a device used for measuring the ratio of methanol penetration enthalpy for water penetrating enthalpy. Fig. 2 is a schematic cross-sectional view showing a direct methanol fuel cell according to an embodiment of the present invention. [Description of main components] 1 : Membrane electrode connector 2: Cathode catalyst layer 3: Anode catalyst layer 4: Cathode gas diffusion layer 5: Anode gas diffusion layer 6: Solid electrolyte membrane-15- (12) (12) 200805770 7a: Cathode conductive layer 7b: Anode conductive layer 8a: Cathode sealing material 8b: Anode sealing material 9: Liquid fuel pool I 〇: Gas-liquid separation membrane II: Frame 1 2: Vapor storage chamber 13: Moisture plate 1 4 : Air introduction port 15: Housing 21: Η-type battery 22: Solid electrolyte membrane 23a, 23b: Connection tubes 24a, 24b: Cylindrical tube 25: Holding member-16-