JP2010129533A - Separator of flat plate system solid electrolyte type fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a separator including an aluminum base material and an aluminum alloy base material that solve the problem of a pin hole generated in application of plating, and to provide a compact and lightweight flat plate system solid electrolyte type fuel cell excellent in cost performance and heat radiating property. <P>SOLUTION: An electrically conductive and corrosion-resisting metal such as Ti is thermally sprayed or plated on aluminum or an aluminum alloy. Then, polishing is performed to increase the smoothness and uniformity of the surface and anodization is performed to increase the corrosion resistance. Then, an electrically insulating anodized film is treated to ion-impregnate a highly electrically conductive metal such as Ag, Au into a several-micron spongy gap between the anodized film and a thermal-sprayed layer by secondary electrochemical machining to ensure the electrical conductivity which is not more than several mΩ in surface resistance value or in cooperation with the thermally sprayed layer made of the electrically conductive and corrosion resisting metal such as Ti. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、小型軽量であり、且つ、低コストである、平板方式固体電解質型燃料電池のセパレーター製造法に関するものである。  The present invention relates to a method for producing a separator for a flat plate type solid oxide fuel cell, which is small and light and low in cost.

平板方式固体電解質型燃料電池の本体部分は固体電解質の膜を挾んでその一方の面に空気極、他の一方の面には燃料極が積層され、空気極側に空気を、燃料極側に水素を含む燃料ガスを供給して発電するよう構成されている。そして、空気極，固体電解質，燃料極からなるセルと、各セルを挟んで燃料ガスや空気を遮断する役割を果たす板状の通気溝を備える部品がセパレーターである。  The main body of the flat plate type solid oxide fuel cell is sandwiched with a solid electrolyte membrane and an air electrode on one side, a fuel electrode on the other side, and air on the air electrode side and air on the fuel electrode side. The fuel gas containing hydrogen is supplied to generate electricity. A separator includes a cell including an air electrode, a solid electrolyte, and a fuel electrode, and a plate-shaped ventilation groove that serves to block fuel gas and air between the cells.

セパレーターは、各セルをシールする機能の他に、燃料ガスや空気を送り込む機能を担う。他に、電気導電性、耐蝕性、放熱性などを要求され材料特性面では調整の難しい部品である。  The separator has a function of feeding fuel gas and air in addition to a function of sealing each cell. In addition, it is a component that requires electrical conductivity, corrosion resistance, heat dissipation, etc. and is difficult to adjust in terms of material characteristics.

セパレーターの製法は、初期のプロトタイプで使われていた「手作り品」と、実用化・量産化を目指す「成形品」とに大別されるが、コストの面から「成形品」が主流を成す。「成形品」は、材料面でカーボン系と金属系の二つに分けられるが、カーボン系は、その厚さが必要であり、幾層にも積層される為に燃料電池そのものの小型化が達成できないと同時に放熱性にも問題がある。また、金属は、アルミがメッキ技術を使用するためにピンホールから局部腐食を起こす問題が解決されていないのでステンレス鋼が主流となっている。しかし、ステンレス鋼は比重が重く、燃料電池全体の重量が重くなり、その性能に比べてその重量が過大なエネルギー消費の元凶となっている。  Separator manufacturing methods can be broadly divided into “handmade products” used in early prototypes and “molded products” aimed at commercialization and mass production, but “molded products” are the mainstream in terms of cost. . “Molded products” can be divided into two types, carbon and metal, in terms of material, but the thickness of the carbon type is necessary, and the fuel cell itself is downsized because it is stacked in layers. At the same time, there is a problem with heat dissipation. In addition, stainless steel is the mainstream metal because the problem of causing local corrosion from pinholes because aluminum uses plating technology has not been solved. However, stainless steel has a high specific gravity, which increases the weight of the fuel cell as a whole, and its weight is a cause of excessive energy consumption compared to its performance.

セパレーターの製法として、コスト面に優れる「成形品」の中で、軽量、小型化、放熱性が見込めるアルミ及びアルミ合金を使用し、メッキ技術より起こるピンホール、即ち、耐蝕性に劣る部分を解決する。  As a manufacturing method of separator, among the "molded products" that are excellent in cost, use aluminum and aluminum alloy that can be expected to be lightweight, downsized, and heat dissipation, and solve the pinholes that occur due to plating technology, that is, the parts with poor corrosion resistance To do.

アルミ金属及びアルミ合金に耐蝕性と電気導電性を同時に叶える為にＴｉなどの電気導電性であり、且つ、耐蝕性である金属を溶射又はメッキする。その後、表面の平滑度を向上させるために研摩する。その厚さは反応ガスを流す溝が必要なために数ミリとする。  In order to simultaneously provide corrosion resistance and electrical conductivity to an aluminum metal and an aluminum alloy, a metal having electrical conductivity such as Ti and corrosion resistance is sprayed or plated. Thereafter, polishing is performed to improve the smoothness of the surface. The thickness is several millimeters because a groove for the reaction gas flow is necessary.

溶射層には、数ミクロンのスポンジ状の間隙が存在しメッキ層にはピンホールが存在するため耐蝕性をまかなうことができないので、基材のアルミ金属及びアルミ合金に陽極酸化処理を為す。すると、メッキのピンホールや溶射層の数ミクロンの間隙を介し基材アルミ金属及びアルミ合金に陽極酸化膜が生成し、メッキのピンホールや溶射層の数ミクロンのスポンジ状の間隙を埋めて耐蝕性を向上させる。その後、電気絶縁性の陽極酸化膜にＡｇやＡｕなどの耐蝕性、高電気導電性の金属を二次電解加工により陽極酸化膜と溶射層の数ミクロンのスポンジ状の間隙にイオン含浸させ、Ｔｉなどの電気導電性であり、且つ、耐蝕性である金属の溶射層と相まって数ミリΩ以下の表面抵抗値ないし断面抵抗値の電気導電性を確保する。  Since the sprayed layer has a sponge-like gap of several microns and the plated layer has pinholes, corrosion resistance cannot be provided. Therefore, anodization is performed on the aluminum metal and aluminum alloy of the base material. As a result, anodized film is formed on the base aluminum metal and aluminum alloy through a gap of several microns in the plated pinhole and the sprayed layer, and the corrosion resistance is filled by filling the sponge-like gap of several microns in the plated pinhole and the sprayed layer. Improve sexiness. After that, an electrically insulating anodic oxide film is impregnated with a corrosion-resistant, highly electrically conductive metal such as Ag or Au in a sponge-like gap of several microns between the anodic oxide film and the sprayed layer by secondary electrolytic processing. The electrical conductivity of a surface resistance value or a cross-sectional resistance value of several milliohms or less is ensured in combination with a metal sprayed layer that is electrically conductive and corrosion resistant.

本発明によると、平板方式固体電解質型燃料電池の構成材であるセパレーターとして耐蝕性に優れ、且つ、高い電気導電性（低い電気抵抗値）を有し、燃料電池本体の性能に対してのコスト軽減、軽量小型化を実現し、省エネルギー、地球環境破壊改善に大きく貢献する。  According to the present invention, the separator as a constituent material of the flat plate type solid oxide fuel cell is excellent in corrosion resistance, has high electrical conductivity (low electrical resistance value), and costs for the performance of the fuel cell main body. Realizing reduction, light weight and downsizing, greatly contribute to energy saving and improvement of global environmental destruction.

Claims (1)

セルを挟むセパレーターがアルミ金属及びアルミを含有する合金であり、その表面に電気導電性であり、且つ、耐蝕性能の高い金属をメッキ又は溶射した後に研摩とアルミ金属及びアルミを含有する合金陽極酸化処理と二次電解処理が為されて製造されていることを特徴とするセパレーター。  The separator that sandwiches the cell is an aluminum metal and an alloy containing aluminum, and the surface thereof is electrically conductive, and after plating or spraying a metal with high corrosion resistance, polishing and anodization of the alloy containing aluminum metal and aluminum A separator characterized by being manufactured by a treatment and a secondary electrolytic treatment.