201036240 六、發明說明： 【發明所屬之技術領域】 本發明係與燃料電池有關，尤指一種可提高微孔層平 整性、均勻度，並有效減少微孔層產生裂縫的燃料電池之 膜電極組。 【先前技術】 〇 按，低溫型燃料電池，例如:PEMFC、DMFC，主要的 核心元件為膜電極組（membrane electrode assembly， MEA) ’常見的膜電極組包含質子交換膜、陰極與陽極觸媒 層、陰極與陽極氣體擴散層五層結構。當燃料電池開始運 作時’氮氣會從陽極氣體擴散層進入到陽極觸媒層產生反 應’放出電子與氫離子，接著氫離子、電子分別經由質子 交換膜、外部線路來到陰極觸媒層，與來自陰極氣體擴散 〇 層的氧氣（或空氣）反應產生水。換言之，觸媒層是反應發 •生的地方，質子交換膜則提供了氫離子傳導的路徑；而氣 體擴散層則扮演了氣體供應、水分排除、電子傳遞的通路。 承上，氣體擴散層必須要具透氣性、疏水性以及高導 電度’加上氣體擴散層直接與觸媒塗佈薄膜（catalyst coated membrane，CCM)接觸，必須具有良好的平整性，以 降低表面接觸電阻，並且確保不會造成CCM損傷，而降低 燃料電池效能。美國專利US4,248,682、US 4,293,396揭露 201036240 了多種可用來當作氣體擴散層的材f，包括金屬網、多孔 性碳板或石墨板、破紙、碳布等。其中非貴金屬（錄、鐵） 的金屬網的化學敎性較差，容易產生腐#，而責金屬 (銀、翻）的金屬網價格過高，均不適用；而多孔碳板或石 墨板’因為強度較弱，厚度料降低，糾賴擴散；因 此質輕、多孔且導電性良好的碳紙、碳布最適合做為燃料 電池氣體擴散層的基材，而於碳纖維基材塗佈鐵氟龍(四氣 化乙烯’ PTFE)，則可增加其疏水性，增強排水功能，減少 膜電極組（MEA)淹水程度。但是，塗佈過多鐵氟龍(pTFE) 加強疏水’會使碳纖維基材本身的電阻升高，因此上述專 利揭露了-種應用在碳纖維基材上的碳/鐵氟龍(c/pTFE) 塗佈層，此層結構兼具疏水性、導電性，且大大提高燃料 電池的電化學效能；此項發展可視為氣體擴散層微孔層 (micro p〇n)US layer，MPL)研究開端。 〇 而微孔層發展至今，除了必須具有良好的排水性、導 電性外，也需具備下列幾項功能： (1)改變氣體擴散層孔洞分布： 由於錢與碳布本身的孔以，雖㈣氣度佳，但氣體 擴散均勻性較差，容紐Μ層局部位置反應過於激烈 而產生熱點_ spot) ’有害於大型燃料電池堆的耐久 性。而微孔層能提供適切的、均句的孔經分布，因此氣 201036240 體均勻擴散到觸媒層，可讓反應均勻發生在整個反應區 間，此外，微孔層的孔洞孔徑較小，搭配基材本身的較 大的孔’/同，能引發毛細力，增強氣體擴散層排水能力。 (2)高平整性與均勻性： 由於碳紙、碳布本身的表面粗糙度較高，在膜電極組 (MEA)製作時’會導致觸媒層與氣體擴散層之間產生較 间的接觸電阻；此外，碳紙、碳布容易有細微、堅硬的 〇 碳纖維突出於表面’容易刺穿質子交換膜造成細微短 路’降低燃料電池效能；因此微孔層必須能提高氣體擴 散層表面平整度，且須完全覆蓋住基材表面，降低突出 纖維接觸到質子交換膜的機率。 為了達到上述目的，微孔層要盡可能形成連續、平整 的表面且要減少裂缝生成，一旦有裂缝，除了增加突出纖 維接觸到質子交換膜的機率，裂縫斷裂面也容易對質子交 G 換膜產生傷害；另外’當採用GDE(gas diffusion electrode) 製程時’觸媒漿料也容易陷入微孔層的裂縫，造成觸媒使 用量增加、利用率下降。 微孔層漿料的成分主要包括：碳黑以及氟化樹脂。美 國 US 4,313,972、US 4,447,505、US 4,647,359、US 5,677,074 等專利揭露了單一或混合使用不同氟化樹脂(例如：PTFE、 PVDF、p〇ly-HFPO等，以及其共聚合物）應用於增加碳纖 5 201036240 維基材疏水性之可能性；美國專利US 4,313,972亦揭露了 多種破材料’例如：碳黑（carbon black)、乙快黑(acetylene black)、石墨’皆可應用於c/PTFE塗佈層之製作。然而， 碳黑與氟化樹脂在水中的分散不佳，必須藉助添加劑幫助 其分散，美國專利US4，185，145、US 4,313,972則分別揭露 了利用非離子型界面活性劑可增加碳黑或氟化樹脂於水中 的分散性。另，美國專利us 6，1〇3,〇77、us 6,444 6〇2 B1 更進一步揭露了多種使用於微孔層漿料的穩定劑 (stabilizer)、增稠劑（thickener)。 而亂體擴散層製程部分，如美國US 4,313,972揭露了 基本的SL程·首先，碳纖維基材(碳紙或碳布）必須進行疏 水作業’接著塗佈微制㈣於雜祕材上，經過供乾、 燒結微孔層後，完成整個肋。而美國專利US 6，127,059 則進-步揭露製作微孔層時，微孔職料渗人碳布的距離 科超過碳布厚度的二分之―，最好以、於三分之一，避 身的孔隙被填滿，造成氣體擴散能力降低;為了 結等程^ 2碳布本身必須先完成含浸疏水劑溶液、燒 :，在真藉由其疏水性使水性轉滲人量減少。然 水性漿料往往t發現：若碳纖維基材本身完成疏水程序， 丨容易形成完整聽，以至於後續供乾、燒 結時，微孔層容m供乾、燒 4產生裂痕、脫落料 201036240 性降低。美國專利US 6,733,915揭露在製作微孔層時，可 使用多種非結晶、半結晶型氟化樹脂，可調整氣體擴散層 的親疏水性、軟硬度，並達到降低烘乾溫度、無需高溫燒 結的目的；但是’其整個製程完全使用有機溶劑，容易對 人員安全造成傷害，且不環保；再者，美國專利US 7，144,476 B2揭露了如何製作連續成捲的碳纖維紙 ，以及連續單面、 -雙面製作微孔層時’如何造成具孔洞分佈梯度的氣體擴散 〇 層之技術手段。 惟’上述所有的先前專利，主要強調碳黑、氟化樹脂 的選擇’以及如何改善微孔層製程達到所需的孔洞分布， 然而卻未能說明如何解決微孔層於製作時發生龜裂現象， 而易對燃料電池中之觸媒層造成破壞，並進而損害燃料電 池耐久性之問題，因此，如何改善上述缺失，即為本發明 所欲解決之首要課題。 〇 【發明内容】 本發明之主要目的，在於提供一種燃料電池之膜電極 組，其係藉由添加高長徑比、高導電度之碳材料於微孔層 漿料中，作為微孔層的結構補強材，有助於降低微孔層漿 料經過烘乾、燒結所造成的應力收縮，能有效減少微孔層 裂縫’改善微孔層平整性、均勻性。 201036240 為達前述之目的，本發明係提供一種燃料電池之膜 極組，其中心為具備離子傳導性之質子交換膜，並於質子 交換膜兩旁各具有-陽極觸媒層及—陰極觸媒層，而 極組最外㈣為-_氣_散層及—氧化驗擴散層， 並於至少其中一觸媒層與氣體擴散層之間塗佈有一微孔 漿料而形成有一微孔層，而微孔層漿料之主要成分由碳黑 以及氟化樹脂組成，並於微孔層漿料中更添加有適量具言 長徑比以及高導電度之碳材料作為微孔層之結構補強材^ 而本發明之上述及其他目的與優點，不難從下述所選 用實施例之詳細說明與附圖中，獲得深入了解。 【實施方式】 首先請配合參閱第1圖，圖中所示者係為本發明所選 用之實施例，此僅供說明之用，在專利申請上並不受此種 結構之限制。 本發明所提供之一種燃料電池之膜電極組1 〇，其主 要係由質子交換膜1 1、一陽極觸媒層1 2與一陰極觸媒 層13、一燃料氣體擴散層14與一氧化氣體擴散層1 5 之五層結構，其中： 該膜電極組1〇之中心係為具備離子傳導性之質子交 換膜11，並於該質子交換膜11兩旁各具有該陽極觸媒 層1 2及該陰極觸媒層1 3，而該膜電極組1 〇最外層則 為該燃料氣體擴散層i 4及該氧化氣體擴散層丄5，並於 至少其中一觸媒層1 2、1 3與氣體擴散層丄4、丄5之 201036240 間塗佈有一由水性微孔層漿料所形成之微孔層i 6，而該 水性微孔層漿料之主要成分係由碳黑以及氟化樹脂組成， 並於該水性微孔層漿料中更添加有適量具高長徑比以及高 導電度之碳材料1 6 1作為微孔層之結構補強材。 上述具高長徑比以及高導電度之碳材料i 6工係可由 碳纖維、超細碳纖維、氣相生長碳纖維或奈米碳管其中之 一所構成。 〇 ❿本發_將此類高長徑比的碳材料i 6 i視為結構 補強材，因為：此類的材料本身具有高剛性、高強度與優 越之物理性質以及微米甚至奈米級的纖維結構，常被用做 結構補強材，加上碳或石墨材料導電性高，不影響微孔層 1 6導電度，並可補強微孔層1 6強度，以減少微孔層龜 裂、斷裂等問題，因此非常適合添加於微孔層漿料。 在微孔層製程部分，此改良後的微孔層漿料，塗佈後 ❹不易滲入氣體擴散層之碳纖維基材，因此碳纖維基材本身 無須先完成疏水程序即可塗佈微孔層，而可避免碳纖維基 材先行完成疏水後，水性微孔層漿料不易施作的問題。 接著針對本發明微孔層之製程步驟，說明如下： ⑴將碳纖維基材:¾含浸水性氣化_旨錄，再設法除去水 分，烘乾方法不限於烘箱烘乾、減壓乾燥、室溫乾燥等， 之後可選擇氟化樹脂進行或不進行燒結。 (2)塗佈微孔層漿料於經過上述步驟⑴處理後的碳纖維基 201036240 材，塗佈方法不限於含浸、轉印、滾輪塗伟、網印、刮 刀塗佈、淋幕塗佈、狹縫式塗佈等。 (3) 以高於100度c，低於300度C的溫度，在空氣中或減 壓抽氣下烘乾’除去微孔層漿料的溶劑以及各類添加劑。 (4) 在350度至400度C之間的溫度，燒結微孔層中的氣化 樹脂’甚至燒結碳纖維基材原先未燒結的氟化樹脂。 (5) 以上製程可階段式、依序製作，或者連績製作。 兹再以下述試驗例更明確解釋本發明。然而，應了解 本發明不以任何方式受限於該等實施例。 試驗例一： 一、製成習用對照組： 首先，係製成習用微孔層漿料之對照組，其成份具有： 碳黑（Vulcan XC-72R) 320g、天然鱗片石墨（尺寸小於 400mesh)5g、商用水性鐵氟龍溶液(含40 wt % PTFE) 2〇〇g、分散劑(Triton X-100) 40g、乙二醇 600g、去離子水 2000g;並將所有成分混合後，先以攪拌設備低速攪拌一小 時’再經球磨機研磨二小時，最後在以200 mesh的濾網過 濾之，得到對照組漿料A。 (1 )將習用微孔層漿料（對照組漿料A)運用至以碳紙 作為碳纖維基材之試驗： 採用已完成疏水的碳紙（CeTechN0S1002)作為碳纖 維基材’將漿料A以刮刀塗佈的方式塗佈於碳紙上，在15〇 201036240 度c的烘箱烘乾30分鐘，再置於37〇度的烘箱中i5分鐘， 得到樣品A1，其微孔層厚度約為60?m。並請參照第2圖 所示’其係為樣品A1微孔層表面放大200倍的影像。 (2 )將習用微孔層漿料（對照組漿料a)運用至以碳布 作為碳纖維基材之試驗： 採用已完成疏水的碳布（CeTech W0S1002)作為礙纖維 -基材，將漿料A以滾輪塗佈的方式塗佈於碳布上，在15〇 度C的烘箱烘乾30分鐘，再置於370度的烘箱中15分鐘 付到樣A2，其微孔層厚度約為6〇? m。並請參照第3圖 所示’其係為樣品A2微孔層表面放大200倍的影像。 二、製成本發明之實驗組·· 接著係製成本發明微孔層漿料之實驗組，其成份具 有：碳黑（Vulcan XC-72R) 320g、天然鱗片石墨（尺寸小於 400mesh)5g、商用水性鐵氟龍溶液(含4〇 % pTFE) 2〇〇g、分散劑(Triton X-100) 40g、乙二醇600g、去離子水 ° 2000g，除此之外，再添加多壁型奈米碳管（直徑約30nm， 長度約20 30?m) 3.2g。將所有成分混合後，先以授拌設備 低速攪拌一小時，再經球磨機研磨二小時，最後在以2〇〇 mesh的濾網過濾之，得到本發明之微孔層漿料β。 (1 )將本發明之微孔層漿料（實驗組漿料B)運用至以 碳紙作為碳纖維基材之試驗： 採用已完成疏水的碳紙（CeTechN0S1002)作為碳纖維 11 201036240 基材，將漿料B以刮刀塗佈的方式塗佈於碳紙上，在 150度C的烘箱烘乾30分鐘，再置於37〇度的烘箱中 15分鐘，得到樣品B1，其微孔層厚度約為6〇?π^並請 參照第4圖所示，其係為樣品B1微孔層表面放大2〇〇 倍的影像。 (2 )將本發明之微孔層漿料（實驗組漿料B)運用至 以碳布作為碳纖維基材之試驗： 採用已完成疏水的碳布（CeTech w〇sl〇〇2)作為碳 纖維基材，將漿料B以滾輪塗佈的方式塗佈於碳布上， 在150度C的烘箱烘乾30分鐘，再於置於37〇度的烘 箱中15分鐘，得到樣品B2，其微孔層厚度約為6〇?m。 並请參照第5圖所示，其係為樣品B2微孔層表面放大 200倍的影像。 而如第6圖所示，本發明係藉由添加高長徑比、高導 電度之碳材料於微孔層漿料中，作為微孔層的結構補強材 ，因此可有助於降低微孔層漿料經過烘乾、燒結所造成的 應力收縮，並進而能有效減少微孔層產生裂縫，或降低裂 縫產生時之裂開程度。 "" 並經由比對上述對照組與實驗組之圖片後即可清楚看 出，本發明之微孔層漿料不論應用在碳紙（請比較第2圖斑 第4圖）、碳布（請比較第3圖與第5圖）上，的確均能發揮 其結構補強㈣能，並有效減少微孔層發生龜裂的可能性 ，而藉此即可有效改善微孔層均勻性、平整性、連續性。 此外’本發明微孔層漿料之製作方法，係直接於微孔 12 201036240 層漿料製程中添加高長徑比的碳材料，因此並不會影響整 個製作流程，而可直接應用於既有之微孔層製造技術，且 於微孔層漿料製程中添加高長徑比的碳材料之方法並不會 影響微孔層漿料穩定性，而能應用於滚輪、刮刀、淋幕等 多種主要塗佈方式’有利於製程調整，適用於氣體擴散層 連績、大規模的量產。 再者，此方法採用水為主要溶劑，環保且對人體無害， ❹設備使用後清潔容易，且此方法無須調整、不需增加額外 之生產設備，即可達到改善之目的。 試驗例二： 係將上述試驗例-中之習用對照組與本發明實驗組所 製成A1、B1、A2、B2樣品進行質子交換膜型燃料電池之 單電池測試： 〇 首先準備商用觸媒面積25咖2的觸媒塗佈薄膜（CCM) 兩片，氫氣端一律採用SGL1败:作為氣禮擴散層，空氣 端則是分別採用樣品a卜m作為氣體擴散層，使用相同 組裝程序、設備，域兩組單電池。測試結果如第7圖， 其測試條件如下： (1)劑量比：氫氣：空氣=1.5 : 2.5 ⑵進料溫度··氫氣端65度c;空氣端65度〇 (3)單電池溫度：60度c 13 201036240 (4) 增濕條件：兩極均要增濕，相對濕度為· (5) 流道設計：三蛇型流道 (6) Tafel 掃描速度：5〇mV/5mill 另，準備商用觸媒面積25cm2的觸媒塗佈薄膜（ccM) 7片’氫氣端-律採用SGL1〇BC作為氣體擴散層，空氣 端則疋分別採用樣品A2、於作為氣體擴散層，使用相同 組裝程序、設備，組成兩組單電池。測試結果如第8圖所 示測試條件係與上述組成兩組單電池之條件相同。 並由上述質子交換膜型燃料電池之單電池測試後可證 實·碳纖維基材不論是採用碳紙(請參閱第7圖）或碳布(請 參閱第8圖）’應用本發明所製成之膜電極組，係可有助於 燃料電池的電化學效能提升。 並由以上詳細說明後可知，本發明所構成之燃料電池 之膜電極組係藉由添加高長徑比、高導電度之碳材料於微 孔層聚料中，作為微孔層的結構補強材，有助於降低微孔 層漿料經過烘乾、燒結所造成的應力收縮，能有效減少微 孔層裂縫’改善微孔層平整性、均勻性；此外，裂縫減少 時往往會造成氣體穿透度下降，導致燃料電池效能降低。 但此方法製作的微孔層不但可有效減少裂縫，且經質子交 換模型燃料電池之單電池測試，不影響其效能，顯示其仍 能維持所需的氣體穿透度，而不損害觸媒層，有助於提高 201036240 燃料電池的耐久性，因此本發明在與同類產品相較下係已 具有相當的進步性及實用性，而實已符合專利法之規定， 故本案發明人爰依法提出申請。201036240 VI. Description of the Invention: [Technical Field] The present invention relates to a fuel cell, and more particularly to a membrane electrode assembly of a fuel cell which can improve the flatness and uniformity of a microporous layer and effectively reduce cracks in a microporous layer. . [Prior Art] 低温, low-temperature fuel cells, such as: PEMFC, DMFC, the main core component is membrane electrode assembly (MEA) 'Common membrane electrode group contains proton exchange membrane, cathode and anode catalyst layer , five-layer structure of cathode and anode gas diffusion layers. When the fuel cell starts to operate, 'nitrogen will react from the anode gas diffusion layer to the anode catalyst layer to emit electrons and hydrogen ions, and then the hydrogen ions and electrons respectively reach the cathode catalyst layer through the proton exchange membrane and the external circuit. Oxygen (or air) from the cathode gas diffusion layer produces water. In other words, the catalyst layer is where the reaction occurs, the proton exchange membrane provides a path for hydrogen ion conduction, and the gas diffusion layer acts as a pathway for gas supply, moisture removal, and electron transport. The gas diffusion layer must have gas permeability, hydrophobicity and high conductivity. In addition, the gas diffusion layer is directly in contact with the catalyst coated membrane (CCM), and must have good flatness to reduce the surface. Contact resistance and ensure that CCM damage is not caused and fuel cell performance is reduced. U.S. Patent No. 4,248,682, issued to U.S. Patent No. 4,293,396, the disclosure of which is incorporated herein by reference in its entirety, the entire entire entire entire entire entire entire entire entire entire entire entire entire disclosure Among them, the metal mesh of non-precious metals (recorded, iron) is poor in chemical enthalpy, and it is easy to produce rot #, while the metal mesh of silver (turned over) is too expensive, and neither is applicable; and porous carbon or graphite plate is because The strength is weak, the thickness of the material is reduced, and the diffusion is hindered; therefore, the carbon paper and carbon cloth which are light, porous and electrically conductive are most suitable as the substrate of the gas diffusion layer of the fuel cell, and the Teflon is coated on the carbon fiber substrate. (Four-gasified ethylene 'PTFE) can increase its hydrophobicity, enhance drainage function, and reduce the degree of flooding of membrane electrode assembly (MEA). However, coating too much Teflon (pTFE) to enhance hydrophobicity will increase the electrical resistance of the carbon fiber substrate itself, so the above patent discloses a carbon/teflon (c/pTFE) coating applied to a carbon fiber substrate. The layer of the layer has both hydrophobicity and electrical conductivity, and greatly improves the electrochemical performance of the fuel cell; this development can be regarded as the beginning of the micro-layer micro layer (micro layer) of the gas diffusion layer (microp〇n). The microporous layer has been developed to this day. In addition to having good drainage and conductivity, it also needs to have the following functions: (1) Changing the pore distribution of the gas diffusion layer: Because the money and the carbon cloth itself are holes, although (4) The gas is good, but the gas diffusion uniformity is poor, and the local position of the Μ Μ layer is too intense to produce hot spots. _ spot) ' Harmful to the durability of large fuel cell stacks. The microporous layer can provide a proper and uniform distribution of pores, so that the gas of 201036240 is uniformly diffused to the catalyst layer, which allows the reaction to occur uniformly throughout the reaction zone. In addition, the pore size of the microporous layer is small, and the matrix is small. The larger pores of the material itself can induce capillary forces and enhance the drainage capacity of the gas diffusion layer. (2) High flatness and uniformity: Due to the high surface roughness of carbon paper and carbon cloth itself, when the membrane electrode assembly (MEA) is produced, it will cause a relatively contact between the catalyst layer and the gas diffusion layer. Resistance; in addition, carbon paper, carbon cloth is easy to have fine, hard carbon fiber protruding from the surface 'easy to pierce the proton exchange membrane to cause a slight short circuit' to reduce fuel cell efficiency; therefore, the microporous layer must be able to improve the surface smoothness of the gas diffusion layer, It must completely cover the surface of the substrate to reduce the probability of the protruding fibers contacting the proton exchange membrane. In order to achieve the above purpose, the microporous layer should form a continuous and flat surface as much as possible and reduce the generation of cracks. In addition to cracks, in addition to increasing the probability of the protruding fibers contacting the proton exchange membrane, the fracture surface of the fracture is also easy to change the membrane for proton exchange. In addition, when the GDE (gas diffusion electrode) process is used, the catalyst slurry is also liable to fall into the crack of the microporous layer, resulting in an increase in the amount of catalyst used and a decrease in utilization rate. The components of the microporous layer slurry mainly include: carbon black and a fluorinated resin. US Patent Nos. 4,313,972, 4,447,505, 4,647,359, 5,677,074, et al. disclose the use of different fluorinated resins (eg, PTFE, PVDF, p〇ly-HFPO, etc., and their copolymers) in a single or mixed application for the addition of carbon fiber 5 201036240 The possibility of hydrophobicity of the substrate; U.S. Patent No. 4,313,972 also discloses the use of various materials such as carbon black, acetylene black and graphite to be applied to the c/PTFE coating layer. . However, the dispersion of carbon black and fluorinated resin in water is not good and must be aided by the use of additives. U.S. Patent Nos. 4,185,145 and 4,313,972 disclose the use of nonionic surfactants to increase carbon black or fluorination, respectively. The dispersibility of the resin in water. Further, U.S. Patent Nos. 6,1,3, 〇77, us 6,444 6〇2 B1 further disclose various stabilizers and thickeners for use in the microporous layer slurry. The process of the disordered diffusion layer, such as US 4,313,972, discloses the basic SL process. First, the carbon fiber substrate (carbon paper or carbon cloth) must be subjected to a hydrophobic operation, followed by coating the micro-system (four) on the miscellaneous materials. After drying and sintering the microporous layer, the entire rib is completed. U.S. Patent No. 6,127,059 further discloses that when making a microporous layer, the distance of the microporous material infiltrating the carbon cloth exceeds the thickness of the carbon cloth by two parts, preferably one third, and avoiding the body. The pores are filled, resulting in a decrease in gas diffusion capacity; in order to complete the process, the carbon cloth itself must first complete the impregnation of the hydrophobic agent solution, and burn: the amount of aqueous infiltration is reduced by its hydrophobicity. However, the aqueous slurry often finds that if the carbon fiber substrate itself completes the hydrophobic process, it is easy to form a complete sound, so that when the subsequent drying and sintering are performed, the microporous layer is provided for drying, burning 4, cracking, and falling off material 201036240. . U.S. Patent No. 6,733,915 discloses the use of a variety of non-crystalline, semi-crystalline fluorinated resins in the preparation of microporous layers, which can adjust the hydrophilicity and hardness of the gas diffusion layer, and achieve the purpose of lowering the drying temperature and eliminating the need for high temperature sintering. However, 'the entire process uses organic solvents completely, which is easy to cause harm to personnel safety and is not environmentally friendly. Moreover, US Patent No. 7,144,476 B2 discloses how to make continuous rolls of carbon fiber paper, as well as continuous single-sided, - double When making microporous layers, the technique of how to create a gas diffusion layer with a gradient of pore distribution. However, all of the above prior patents mainly emphasize the choice of carbon black and fluorinated resin, and how to improve the pore distribution of the microporous layer process, but fail to explain how to solve the cracking phenomenon of the microporous layer during production. However, it is easy to damage the catalyst layer in the fuel cell and further impair the durability of the fuel cell. Therefore, how to improve the above-mentioned deficiency is the primary problem to be solved by the present invention. SUMMARY OF THE INVENTION The main object of the present invention is to provide a membrane electrode assembly for a fuel cell by adding a high aspect ratio, high conductivity carbon material to the microporous layer slurry as a microporous layer. The structural reinforcing material helps to reduce the stress shrinkage caused by the drying and sintering of the microporous layer slurry, and can effectively reduce the crack of the microporous layer to improve the flatness and uniformity of the microporous layer. 201036240 For the purpose of the foregoing, the present invention provides a membrane electrode assembly of a fuel cell, the center of which is a proton exchange membrane having ion conductivity, and has an anode catalyst layer and a cathode catalyst layer on both sides of the proton exchange membrane. And the outermost (four) of the pole group is a gas dispersion layer and a diffusion layer, and a microporous slurry is formed between at least one of the catalyst layer and the gas diffusion layer to form a microporous layer. The main component of the microporous layer slurry is composed of carbon black and a fluorinated resin, and a carbon material having an appropriate aspect ratio and high conductivity is added to the microporous layer slurry as a structural reinforcing material of the microporous layer. The above and other objects and advantages of the present invention will be readily understood from [Embodiment] First, please refer to Fig. 1, which is an embodiment selected for the present invention, which is for illustrative purposes only and is not limited by such a structure in the patent application. The membrane electrode assembly 1 of the fuel cell provided by the present invention mainly comprises a proton exchange membrane 11 , an anode catalyst layer 12 and a cathode catalyst layer 13 , a fuel gas diffusion layer 14 and an oxidizing gas. a five-layer structure of the diffusion layer 15 wherein: the center of the membrane electrode group 1 is a proton exchange membrane 11 having ion conductivity, and the anode catalyst layer 12 is provided on both sides of the proton exchange membrane 11 a cathode catalyst layer 13, and the outermost layer of the membrane electrode group 1 is the fuel gas diffusion layer i 4 and the oxidizing gas diffusion layer 丄5, and at least one of the catalyst layers 1-2, and the gas diffusion The layers 3, 丄5, 201036240 are coated with a microporous layer i6 formed by the aqueous microporous layer slurry, and the main component of the aqueous microporous layer slurry is composed of carbon black and a fluorinated resin, and In the aqueous microporous layer slurry, an appropriate amount of carbon material 161 having a high aspect ratio and high conductivity is added as a structural reinforcing material of the microporous layer. The above-mentioned carbon material i 6 system having a high aspect ratio and high conductivity may be composed of one of carbon fiber, ultrafine carbon fiber, vapor grown carbon fiber or carbon nanotube. 〇❿本发_ These high aspect ratio carbon materials i 6 i are considered as structural reinforcements because: such materials themselves have high rigidity, high strength and superior physical properties as well as micron or even nanofibers. The structure is often used as a structural reinforcing material, and the carbon or graphite material has high conductivity, does not affect the conductivity of the microporous layer 16 , and can strengthen the microporous layer 16 to reduce the microporous layer cracking, fracture, etc. The problem is therefore very suitable for addition to the microporous layer slurry. In the microporous layer process portion, the modified microporous layer slurry is not easily infiltrated into the carbon fiber substrate of the gas diffusion layer after coating, so that the carbon fiber substrate itself can be coated with the microporous layer without first completing the hydrophobic process. The problem that the aqueous microporous layer slurry is not easily applied after the carbon fiber substrate is firstly drained can be avoided. Next, the process steps of the microporous layer of the present invention are as follows: (1) Carbon fiber substrate: 3⁄4 impregnated aqueous gasification _ record, and then try to remove moisture, drying method is not limited to oven drying, drying under reduced pressure, drying at room temperature Alternatively, the fluorinated resin may or may not be sintered. (2) coating the microporous layer slurry on the carbon fiber-based 201036240 material after the above step (1), the coating method is not limited to impregnation, transfer, roller coating, screen printing, blade coating, curtain coating, narrow Sewing coating, etc. (3) Drying the solvent of the microporous layer slurry and various additives at a temperature higher than 100 ° C and lower than 300 ° C in air or under reduced pressure. (4) The vaporized resin in the microporous layer is sintered at a temperature between 350 °C and 400 °C, or even the fluorinated resin of the original unsintered carbon fiber substrate is sintered. (5) The above processes can be produced in stages, in sequence, or in succession. The invention will be more specifically explained by the following test examples. However, it should be understood that the invention is not limited to the embodiments in any way. Test Example 1: First, a conventional control group was prepared: First, a control group of a conventional microporous layer slurry was prepared, which had the following components: carbon black (Vulcan XC-72R) 320 g, natural flake graphite (size less than 400 mesh) 5 g Commercial water-based Teflon solution (containing 40 wt% PTFE) 2〇〇g, dispersant (Triton X-100) 40g, ethylene glycol 600g, deionized water 2000g; and mixing all ingredients, first with stirring equipment The mixture was stirred at low speed for one hour and then milled for two hours by a ball mill. Finally, it was filtered through a 200 mesh sieve to obtain a control slurry A. (1) Applying a conventional microporous layer slurry (control sample A) to a test using carbon paper as a carbon fiber substrate: using a hydrophobic carbon paper (CeTech No. 1002) as a carbon fiber substrate 'slurry A as a doctor blade The coating method was applied to carbon paper, dried in an oven at 15 〇 201036240 degrees C for 30 minutes, and placed in an oven at 37 Torr for 5 minutes to obtain a sample A1 having a microporous layer thickness of about 60 μm. Please refer to Fig. 2 for the image of the microporous layer of sample A1 magnified 200 times. (2) Applying a conventional microporous layer slurry (control slurry a) to a test using carbon cloth as a carbon fiber substrate: using a hydrophobic carbon cloth (CeTech W0S1002) as a barrier fiber-substrate, the slurry A is coated on a carbon cloth by roller coating, dried in an oven at 15 degrees C for 30 minutes, and then placed in a 370 degree oven for 15 minutes to give sample A2 with a microporous layer thickness of about 6 〇. ? m. Please refer to Fig. 3 for the image of the microporous layer of sample A2 magnified 200 times. 2. The experimental group of the present invention was prepared. The experimental group of the microporous layer slurry of the present invention was further composed of carbon black (Vulcan XC-72R) 320 g, natural flake graphite (size less than 400 mesh) 5 g, and commercial water. Teflon solution (containing 4% pTFE) 2〇〇g, dispersant (Triton X-100) 40g, ethylene glycol 600g, deionized water ° 2000g, in addition to multi-walled nanocarbon Tube (about 30 nm in diameter, length about 20 30 μm) 3.2 g. After mixing all the ingredients, the mixture was first stirred at a low speed for one hour, then ground by a ball mill for two hours, and finally filtered through a 2 〇〇 mesh filter to obtain a microporous layer slurry β of the present invention. (1) Application of the microporous layer slurry of the present invention (experimental slurry B) to carbon paper as a carbon fiber substrate: Using a hydrophobic carbon paper (CeTech No. 1002) as a carbon fiber 11 201036240 substrate, a slurry Material B was applied to carbon paper by knife coating, dried in an oven at 150 ° C for 30 minutes, and placed in an oven at 37 degrees for 15 minutes to obtain sample B1 having a microporous layer thickness of about 6 〇. ?π^ and please refer to Fig. 4, which is an image of the surface of the sample B1 microporous layer magnified 2 times. (2) Application of the microporous layer slurry of the present invention (experimental slurry B) to a carbon fiber substrate as a carbon fiber substrate: Using a hydrophobic carbon cloth (CeTech w〇sl〇〇2) as a carbon fiber base The slurry B was coated on a carbon cloth by roller coating, dried in an oven at 150 ° C for 30 minutes, and placed in an oven at 37 ° C for 15 minutes to obtain a sample B2, which was microporous. The layer thickness is about 6 〇 m. Please refer to Fig. 5, which is an image magnified 200 times of the surface of the microporous layer of sample B2. As shown in FIG. 6, the present invention is useful as a structural reinforcing material for a microporous layer by adding a high aspect ratio, high conductivity carbon material to the microporous layer slurry, thereby contributing to the reduction of micropores. The stress of the layer slurry is dried and sintered, and the crack of the microporous layer is effectively reduced, or the degree of cracking when the crack is generated is reduced. "" And by comparing the pictures of the above control group and the experimental group, it can be clearly seen that the microporous layer slurry of the present invention is applied to carbon paper (please compare the second figure 4), carbon cloth (Please compare Fig. 3 and Fig. 5), it can really exert its structural reinforcement (4) energy, and effectively reduce the possibility of cracking in the microporous layer, thereby effectively improving the uniformity and flatness of the microporous layer. Sexuality, continuity. In addition, the method for preparing the microporous layer slurry of the present invention directly adds the high aspect ratio carbon material directly to the microporous 12 201036240 layer slurry process, so that the entire production process is not affected, and can be directly applied to the existing The microporous layer manufacturing technology, and the method of adding a high aspect ratio carbon material in the microporous layer slurry process does not affect the stability of the microporous layer slurry, but can be applied to various rollers, scrapers, curtains, and the like. The main coating method is favorable for process adjustment, and is suitable for gas diffusion layer performance and large-scale mass production. Furthermore, this method uses water as the main solvent, is environmentally friendly and harmless to the human body, and is easy to clean after use, and this method can be improved without adjustment or additional production equipment. Test Example 2: The single cell test of the proton exchange membrane type fuel cell was carried out by using the conventional control group in the above test example and the experimental group of the present invention, and the A1, B1, A2, and B2 samples were prepared: 〇 First, the commercial catalyst area was prepared. 25 coffee 2 catalyst coated film (CCM) two pieces, the hydrogen end is always SGL1 defeat: as the gas diffusion layer, the air end is the sample a b m as the gas diffusion layer, using the same assembly procedures, equipment, Field two sets of single cells. The test results are shown in Figure 7. The test conditions are as follows: (1) Dose ratio: hydrogen: air = 1.5: 2.5 (2) feed temperature · · hydrogen end 65 degrees c; air end 65 degrees 〇 (3) cell temperature: 60 Degree c 13 201036240 (4) Humidification conditions: Both sides are humidified, relative humidity is (5) Flow path design: Three snake flow path (6) Tafel Scanning speed: 5〇mV/5mill Another, ready for commercial touch Catalyst coated film (ccM) with a media area of 25 cm2 7 pieces of 'hydrogen end-law using SGL1〇BC as a gas diffusion layer, and air end with sample A2, respectively, as a gas diffusion layer, using the same assembly procedure and equipment, Form two sets of single cells. The test results are as shown in Fig. 8 and the test conditions are the same as those described above for forming two sets of single cells. And it can be confirmed by the single cell test of the above proton exchange membrane type fuel cell. The carbon fiber substrate is made of carbon paper (see Fig. 7) or carbon cloth (see Fig. 8). Membrane electrode sets can contribute to the electrochemical performance improvement of fuel cells. As can be seen from the above detailed description, the membrane electrode assembly of the fuel cell constructed by the present invention is a structural reinforcing material for the microporous layer by adding a carbon material having a high aspect ratio and high conductivity to the microporous layer. It can help reduce the stress shrinkage caused by drying and sintering of the microporous layer slurry, and can effectively reduce the microporous layer cracks' to improve the flatness and uniformity of the microporous layer; in addition, the gas penetration can be caused when the crack is reduced. Decreased, resulting in reduced fuel cell performance. However, the microporous layer produced by this method can not only effectively reduce cracks, but also the single cell test of the proton exchange model fuel cell does not affect its performance, indicating that it can maintain the required gas permeability without damaging the catalyst layer. , which helps to improve the durability of the 201036240 fuel cell. Therefore, the present invention has been quite advanced and practical in comparison with similar products, and has actually complied with the provisions of the Patent Law, so the inventor of the present invention filed an application according to law. .
〇 15 201036240 【圖式簡單說明】 第1圖係本發明之結構示意圖 第2圖係以習用微孔層漿料所製成之樣品Ai其微孔層 表面放大200倍之影像圖 第3圖係以習用微孔層漿料所製成之樣品…其微孔層 表面放大200倍之影像圖 第4圖係以本發明微孔層漿料所製成之樣品B1其微孔 層表面放大200倍之影像圖 第5圖係以本發明微孔層漿料所製成之樣品B2其微孔 層表面放大200倍之影像圖 第6圖係本發明微孔層於產生裂缝時之狀態示意圖 第7圖係為採用樣品Al、B1作為氣體擴散層，並使 用相同組裝程序、設備，組成兩組單電池所 進行之質子交換膜型燃料電池之單電池測試 圖 第8圖係為採用樣品A2、B2作為氣體擴散層，並使 用相同組裝程序、設備，組成兩組單電池所 進行之質子交換膜型燃料電池之單電池測試 圖 質子交換膜11 【主要元件符號說明】 膜電極組1 0 201036240〇15 201036240 [Simplified illustration of the drawings] Fig. 1 is a schematic view showing the structure of the present invention. Fig. 2 is a diagram of a sample Ai prepared by using a conventional microporous layer slurry, and the surface of the microporous layer is magnified 200 times. A sample prepared by using a microporous layer slurry, the surface of the microporous layer is magnified 200 times. Fig. 4 is a sample B1 made of the microporous layer slurry of the present invention, and the surface of the microporous layer is magnified 200 times. Fig. 5 is a view showing a state in which the surface of the microporous layer of the sample B2 prepared by the microporous layer slurry of the present invention is magnified 200 times. Fig. 6 is a view showing the state of the microporous layer of the present invention in the case of crack generation. The picture shows the single cell test chart of the proton exchange membrane type fuel cell using the sample Al and B1 as the gas diffusion layer and using the same assembly procedure and equipment to form two sets of single cells. The eighth picture shows the sample A2 and B2. As a gas diffusion layer, and using the same assembly procedure and equipment, a single cell test pattern proton exchange membrane 11 of a proton exchange membrane type fuel cell composed of two sets of single cells is used. [Main component symbol description] Membrane electrode group 1 0 201036240
陽極觸媒層12 陰極觸媒層13 燃料氣體擴散層14 氧化氣體擴散層15 微孔層16 碳材料161 17Anode catalyst layer 12 Cathode catalyst layer 13 Fuel gas diffusion layer 14 Oxidation gas diffusion layer 15 Microporous layer 16 Carbon material 161 17