JP2542096B2 - How to stop the fuel cell - Google Patents
How to stop the fuel cellInfo
- Publication number
- JP2542096B2 JP2542096B2 JP1333940A JP33394089A JP2542096B2 JP 2542096 B2 JP2542096 B2 JP 2542096B2 JP 1333940 A JP1333940 A JP 1333940A JP 33394089 A JP33394089 A JP 33394089A JP 2542096 B2 JP2542096 B2 JP 2542096B2
- Authority
- JP
- Japan
- Prior art keywords
- fuel
- fuel cell
- positive electrode
- utilization rate
- air
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/24—Grouping of fuel cells, e.g. stacking of fuel cells
- H01M8/241—Grouping of fuel cells, e.g. stacking of fuel cells with solid or matrix-supported electrolytes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
- H01M8/04223—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells
- H01M8/04228—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells during shut-down
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
- H01M8/04298—Processes for controlling fuel cells or fuel cell systems
- H01M8/043—Processes for controlling fuel cells or fuel cell systems applied during specific periods
- H01M8/04303—Processes for controlling fuel cells or fuel cell systems applied during specific periods applied during shut-down
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/24—Grouping of fuel cells, e.g. stacking of fuel cells
- H01M8/2457—Grouping of fuel cells, e.g. stacking of fuel cells with both reactants being gaseous or vaporised
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Fuel Cell (AREA)
Description
【発明の詳細な説明】 ［産業上の利用分野］ この発明は燃料電池の停止方法に関するものである。TECHNICAL FIELD The present invention relates to a method of stopping a fuel cell.
［従来の技術］ 白金などの貴金属を触媒とする燃料電池発電システム
では、燃料電池を停止する際に正極の電位が高くなり、
白金の溶出、カーボンの腐食などにより電池の性能が低
下するという問題点があった。[Prior Art] In a fuel cell power generation system using a precious metal such as platinum as a catalyst, the potential of the positive electrode becomes high when the fuel cell is stopped,
There is a problem that the performance of the battery is deteriorated due to elution of platinum, corrosion of carbon and the like.
正極の電位が高くなった場合の問題点については、例
えば特開昭59−211970号公報に示されているが、この問
題点を解決するためにこれまでにいくつかの方法が提案
されている。例えば特公昭60−10425号公報には酸化剤
の排気を入口側へ再循環させ、酸素分圧を低下させるこ
とで正極の電位が高くなるのを防止する方法が示されて
いる。しかし、再循環させるためにはリサイクルブロワ
ー及びその補機動力を必要とするため、高コストになり
実用的ではなかった。特に200KW以下の燃料電池システ
ムには、コンパクト化も要求されるのでこの方法は適用
が困難であった。この他、低負荷時に燃料電池の出力電
圧を低下させる方法として、特開昭60−177565号公報に
は、不活性ガスを反応ガスに混入させたり、反応ガスの
利用率を増加させて出力電圧を低下させる方法が示され
ているが、大量の不活性ガスを常に用意しておく必要が
あること、燃料の水素利用率を上昇させると正極や負極
が腐食してしまうという問題点があった。The problem when the potential of the positive electrode becomes high is shown in, for example, JP-A-59-211970, but some methods have been proposed so far in order to solve this problem. . For example, Japanese Examined Patent Publication No. 60-10425 discloses a method in which the exhaust gas of the oxidant is recirculated to the inlet side to reduce the oxygen partial pressure to prevent the potential of the positive electrode from increasing. However, the recycler requires a recycle blower and its auxiliary machine power, which is expensive and impractical. In particular, this method is difficult to apply to a fuel cell system of 200 KW or less, because downsizing is also required. In addition, as a method of lowering the output voltage of the fuel cell at a low load, JP-A-60-177565 discloses mixing an inert gas into a reaction gas or increasing the utilization rate of the reaction gas to increase the output voltage. However, there is a problem that it is necessary to always prepare a large amount of inert gas and that the positive and negative electrodes are corroded when the hydrogen utilization rate of the fuel is increased. .
［発明が解決しようとする課題］ 従来の燃料電池発電システムでは、燃料電池を停止す
る際に正極の電位が高くなり、白金の溶出、カーボンの
腐食などにより電池の性能が低下し、種々の方法が講じ
られているが、いずれも高コストになり実用的ではなか
った。また、低負荷時に燃料電池の出力電圧を低下させ
る方法として、不活性ガスを反応ガスに混入させたり、
反応ガスの利用率を増加させて出力電圧を低下させる方
法が示されているが、大量の不活性ガスを常に用意して
おく必要があること、燃料の水素利用率を上昇させると
正極や負極が腐食してしまうという問題点があった。[Problems to be Solved by the Invention] In the conventional fuel cell power generation system, the potential of the positive electrode becomes high when the fuel cell is stopped, and the performance of the cell deteriorates due to elution of platinum, corrosion of carbon, etc. However, all of them were expensive and not practical. Also, as a method of lowering the output voltage of the fuel cell at a low load, by mixing an inert gas with the reaction gas,
Although a method of increasing the utilization rate of the reaction gas and lowering the output voltage has been shown, it is necessary to always prepare a large amount of inert gas. There was a problem that it would be corroded.
この発明は上記のような問題点を解消するためになさ
れたもので、補機や不活性ガスを用いずに、正極の電位
が高くなるのを防止することのできる燃料電池の停止方
法を得ることを目的とする。The present invention has been made to solve the above problems, and provides a method for stopping a fuel cell capable of preventing the potential of the positive electrode from becoming high without using an auxiliary machine or an inert gas. The purpose is to
［課題を解決するための手段］ この発明に係る燃料電池の停止方法は、各々が正極と
負極とを有する複数個の燃料電池が、電気的に直列に接
続された燃料電池積層体を有し、酸化剤が各燃料電池の
正極に接する空気流路へ供給され、燃料が各燃料電池の
負極に接する燃料流路へ供給されて発電し、外部負荷
（以下、単に、負荷ともいう）を繋いで外部負荷および
燃料電池に電流を流して運転される燃料電池において、
外部負荷を繋いで外部負荷および燃料電池に電流を流し
た状態で、燃料の水素利用率を90％以下に保ち、かつ、
酸化剤の酸素利用率を85％以上に上げて正極内で前記水
素を発生させた後、外部負荷を切って運転を停止するよ
うにしたものである。[Means for Solving the Problems] A method of stopping a fuel cell according to the present invention includes a fuel cell stack in which a plurality of fuel cells each having a positive electrode and a negative electrode are electrically connected in series. , The oxidant is supplied to the air flow path in contact with the positive electrode of each fuel cell, and the fuel is supplied to the fuel flow path in contact with the negative electrode of each fuel cell to generate electricity, and connect an external load (hereinafter, also simply referred to as load). In a fuel cell operated by applying an electric current to an external load and a fuel cell with
Keeping the hydrogen utilization rate of the fuel below 90% while connecting the external load and applying current to the external load and the fuel cell, and
The oxygen utilization rate of the oxidant is increased to 85% or more to generate the hydrogen in the positive electrode, and then the external load is turned off to stop the operation.
［作用］ この発明においては、燃料の水素利用率を90％以下に
保つことで白金の溶出やカーボンの腐食の危険性を低下
させ、酸化剤の酸素利用率を85％以上に上げて正極内で
水素を発生させることによって、正極の電位を急速に低
下させることができる。[Operation] In the present invention, maintaining the hydrogen utilization rate of the fuel at 90% or less reduces the risk of platinum elution or carbon corrosion, and raises the oxygen utilization rate of the oxidizer to 85% or more to increase By generating hydrogen at 1, the potential of the positive electrode can be rapidly lowered.
［実施例］ 本発明者らは、どのような運転条件下で正極の電位が
高くなるのかを調べるために24個の参照電極を単セルの
周囲に配設した装置を開発して、セル面内での正極及び
負極の電位の変化を調べた。[Examples] The present inventors have developed a device in which 24 reference electrodes are arranged around a single cell in order to investigate under what operating conditions the potential of the positive electrode becomes high. The changes in the potentials of the positive electrode and the negative electrode inside were examined.
ここで、単セルとしては、有効面積100cm2のリン酸型
燃料電池を用い、たとえば、1989年９月18日発行の『第
40回ISEミーティング（The 40th ISE Meeting）』の
アブストラクト（abstract）の第321頁の第１図および
第２図に示されているように、24個の参照電極（RHE:可
逆水素電極）を負極（アノード、燃料極）および正極
（カソード、酸化剤極）の周囲に並べて各々に純水素を
供給し、24個の参照電極から負極電位（アノード電位）
および正極電位（カソード電位）を測定した。これによ
り、参照電極が多数存在するために、参照電極近傍で起
こっている反応を反映した負極電位および正極電位を測
定することができる。Here, as a single cell, a phosphoric acid fuel cell with an effective area of 100 cm 2 is used. For example, “No. 1” issued on September 18, 1989.
As shown in FIGS. 1 and 2 on page 321 of the abstract of the 40th ISE Meeting, 24 reference electrodes (RHE: reversible hydrogen electrodes) are used as negative electrodes. (Anode, fuel electrode) and positive electrode (cathode, oxidizer electrode) are arranged side by side, and pure hydrogen is supplied to each, and the negative electrode potential (anode potential) from 24 reference electrodes.
And the positive electrode potential (cathode potential) was measured. Thereby, since there are many reference electrodes, it is possible to measure the negative electrode potential and the positive electrode potential that reflect the reaction occurring near the reference electrode.
その結果、燃料の水素利用率が92％〜95％になったと
き燃料出口側の正極の電位が極めて高くなり、また、燃
料の水素利用率が95％を越えたとき燃料出口側の負極の
電位が極めて高くなり、いずれもCO及びCO2の出口ガス
の検知からそれぞれ正極と負極のカーボンの腐食が起こ
っている事実を確認した。As a result, the potential of the positive electrode on the fuel outlet side becomes extremely high when the hydrogen utilization rate of the fuel becomes 92% to 95%, and when the hydrogen utilization rate of the fuel exceeds 95%, the negative electrode potential on the fuel outlet side becomes negative. The electric potential became extremely high, and the fact that carbon in the positive electrode and carbon in the negative electrode were corroded was confirmed from the detection of CO and CO 2 outlet gases.
一方、酸化剤の酸素利用率が85％を超えると正極の電
位が急速に低下して正極内で水素が発生すること、酸素
利用率が100％を超えても電流量に応じて水素の発生量
が増加するだけで、正極の電位は上がらず腐食の危険性
が全くないこともわかった。これらの研究成果は、1989
年９月18日にISE（International Society of Electroc
hemistry）で“Polarization Study of Fuel Cell with
Multi−Reference Electrodes"の題名で発表してい
る。（Abstracts:18−01−13−Ｇ） また、前述の文献『第40回ISEミーティング（The 40
th ISE Meeting）』のアブストラクト（abstract）の
第321頁の第３図には、燃料利用率が90％、92％および9
7％とした場合のセル内の電位分布が示されている。こ
の電位分布によれば、燃料利用率が90％の場合には、カ
ソード（空気極）電位がそれほど高くはならないが、92
％の場合には、燃料出口側のカソード電位が0.8V付近に
まで達し、腐食の危険性が極めて高くなっていることが
分かる。また、この文献の第320頁の記載によれば、実
際に空気極の腐食生成物であるCO（一酸化炭素）および
CO2（二酸化炭素）が検出され、燃料極の腐食が現実に
起こっていることが示されている。On the other hand, if the oxygen utilization rate of the oxidant exceeds 85%, the potential of the positive electrode will rapidly drop and hydrogen will be generated in the positive electrode. Even if the oxygen utilization rate exceeds 100%, hydrogen will be generated according to the current amount. It was also found that the positive electrode potential did not rise and there was no risk of corrosion at all even if the amount increased. The results of these studies are 1989
ISE (International Society of Electroc
hemistry) “Polarization Study of Fuel Cell with
The title is "Multi-Reference Electrodes" (Abstracts: 18-01-13-G).
th ISE Meeting ”on page 321 of the abstract of Figure 3, fuel utilization is 90%, 92% and 9%.
The potential distribution in the cell is shown for 7%. According to this potential distribution, the cathode (air electrode) potential does not become so high when the fuel utilization rate is 90%.
In the case of%, it can be seen that the cathode potential on the fuel outlet side reaches up to around 0.8 V, and the risk of corrosion is extremely high. Further, according to the description on page 320 of this document, CO (carbon monoxide) which is actually a corrosion product of the air electrode and
CO 2 (carbon dioxide) has been detected, indicating that corrosion of the anode is actually occurring.
さらに、この文献の第321頁の第４図には、空気利用
率を58％、84％および161％とした場合のセル面内の電
位分布が示されており、いずれの場合もカソード電位お
よびアソード電位は低く保たれ、腐食の危険性がないこ
とが示されている。このような現象は、この文献の第32
1頁内の第１図および第２図に示された多極参照電極付
き単セルを用いることにより、初めて明らかにされたも
のである。Furthermore, FIG. 4 on page 321 of this document shows the potential distribution in the cell plane when the air utilization rates are 58%, 84%, and 161%. The sword potential is kept low, indicating no risk of corrosion. Such a phenomenon is described in the 32nd article of this document.
It was first clarified by using the single cell with a multipolar reference electrode shown in FIGS. 1 and 2 on page 1.
本発明はこの研究成果をふまえて行われたもので以下
その実施例を示す。The present invention was carried out based on this research result, and the examples thereof will be shown below.
実施例１ 205℃、150mA/cm2常圧で動作中のリン酸型燃料電池の
21セルスタックを用いて実施例１の試験を行った。通
常、酸化剤として空気を用いた場合、供給される空気流
量は、以下のように決定される。Example 1 Example of phosphoric acid fuel cell operating at 205 ° C., 150 mA / cm 2 normal pressure
The test of Example 1 was conducted using a 21 cell stack. Usually, when air is used as the oxidant, the supplied air flow rate is determined as follows.
すなわち、供給した空気に含まれる酸素のうち、60％
が燃料電池のスタックでのカソード反応で消費され（空
気利用率60％）、残りの40％の酸素と窒素とが燃料電池
スタックの出口側に排出されるように、あらかじめ計算
し、計算された空気流量を、フロート式の流量計やマス
フローメータ等の一般的な気体流量を用いて燃料電池ス
タックの空気極側に供給している。That is, 60% of the oxygen contained in the supplied air
Was calculated and calculated so that the gas is consumed by the cathode reaction in the fuel cell stack (air utilization rate of 60%), and the remaining 40% of oxygen and nitrogen is discharged to the outlet side of the fuel cell stack. The air flow rate is supplied to the air electrode side of the fuel cell stack by using a general gas flow rate such as a float type flow meter or a mass flow meter.
なお、酸化剤として、上記空気の代わりに純酸素など
を用いた場合も同様である。また、流量は電流密度や電
極面積に比例するが、流量の計算は、電流密度や電極面
積が分かれば理論的に極めて簡単に求めることができ
る。The same applies when pure oxygen or the like is used as the oxidant instead of the air. Although the flow rate is proportional to the current density and the electrode area, the flow rate can be theoretically extremely easily calculated if the current density and the electrode area are known.
本実施例１では、計算上の空気利用率が120％となる
ように、空気流量を減少させた。このように空気利用率
が100％を超えると、空気極において酸素が100％消費さ
れてしまうとともに水素が発生し始める。すなわち、空
気極の空気入口側の領域では以下の式（１）の反応が起
こり、空気極の空気出口側の領域では以下の式（２）の
反応が起こる。In the first embodiment, the air flow rate is reduced so that the calculated air utilization rate is 120%. Thus, when the air utilization rate exceeds 100%, 100% of oxygen is consumed at the air electrode and hydrogen starts to be generated. That is, the reaction of the following formula (1) occurs in the region on the air inlet side of the air electrode, and the reaction of the following formula (2) occurs in the region on the air outlet side of the air electrode.
O2＋4H+＋4e-→2H2O ……（１） 2H+＋2e-→H2 ……（２） 上記のように、空気利用率が120％であって、たとえ
ば、120A（アンペア）の電流が流れたとすると、100Aは
式（１）の反応で流れ、残りの20Aは式（２）の反応で
流れる。したがって、空気極出口側では、式（２）で発
生した水素が検知されることになる。しかしながら、本
実施例１のように、空気利用率が100％を超えるような
モードによる燃料電池の運転は、これまで全く報告され
ていない。O 2 ＋ 4H + ＋ 4e − → 2H 2 O …… (1) 2H + ＋ 2e − → H 2 …… (2) As mentioned above, the air utilization rate is 120%, for example, the current of 120A (ampere) If 100 flows, 100A flows in the reaction of the formula (1), and the remaining 20A flows in the reaction of the formula (2). Therefore, on the air electrode outlet side, hydrogen generated by the formula (2) is detected. However, the operation of the fuel cell in the mode in which the air utilization rate exceeds 100% as in Example 1 has not been reported at all until now.
なお、燃料極では、式（１）または式（２）の反応の
違いによらず、以下の式（３）の水素酸化反応が、電流
120Aが流れるだけ起こる。In addition, in the fuel electrode, the hydrogen oxidation reaction of the following formula (3) does not depend on the difference in the reaction of the formula (1) or the formula (2).
It happens as 120A flows.
H2→2H+＋2e- ……（３） この結果、空気利用率が100％を超えても、燃料利用
率が高くならない限り、空気極からの水素発生量が増加
するだけで、腐食の危険性は生じないことになる。しか
し、燃料利用率が高くなった場合には、空気利用率が10
0％を超えて空気極で水素が発生していても、燃料極の
腐食の危険性が高くなるので、燃料利用率を90％以下に
保つ必要がある。 H 2 → 2H + + 2e - ...... (3) As a result, even the air utilization rate exceeds 100%, as long as the fuel utilization ratio is not high, only the amount of hydrogen generation from the air electrode is increased, the risk of corrosion Sex will not occur. However, if the fuel utilization rate becomes high, the air utilization rate becomes 10%.
Even if hydrogen exceeds 0% at the air electrode, the risk of corrosion of the fuel electrode increases, so it is necessary to keep the fuel utilization rate below 90%.
すなわち、燃料流量についても、前述の空気流量の場
合と同様に、供給した燃料ガスに含まれる水素のうち、
80％が燃料電池スタックでのアノード反応で消費され
（燃料利用率80％）、残りの20％の水素と二酸化炭素と
が燃料電池スタックの出口側に排出されるように、あら
かじめ計算し、計算された燃料流量をフロート式の流量
計やマスフローメータ等の一般的な気体流量を用いて燃
料電池スタックの燃料極側に供給される。That is, as for the fuel flow rate, as in the case of the air flow rate described above, of the hydrogen contained in the supplied fuel gas,
Calculate and calculate in advance so that 80% is consumed by the anode reaction in the fuel cell stack (fuel utilization rate is 80%) and the remaining 20% of hydrogen and carbon dioxide are discharged to the outlet side of the fuel cell stack. The fuel flow rate is supplied to the fuel electrode side of the fuel cell stack using a general gas flow rate such as a float type flow meter or a mass flow meter.
また、一般に、空気利用率が84％を超えると水素の発
生が起こるので、空気利用率が85％以上に上げて水素を
発生させる必要がある。Further, generally, when the air utilization rate exceeds 84%, hydrogen is generated, so it is necessary to raise the air utilization rate to 85% or more to generate hydrogen.
通常は、電流密度に比例して空気利用率および燃料利
用率が一定に保たれるように、空気流量および燃料流量
が連動して制御されている。しかし、本実施例では、燃
料利用率を75％に保ち、電流密度を150mA/cm2（前述の
ように電極の有効面積が100cm2の場合、15Aの電流に相
当）に保ったまま、空気流量のみを減少させて、空気利
用率を120％まで上昇させた後、５分後負荷及び反応ガ
スの供給を切って運転を停止したこのとき燃料利用率は
75％を維持した。再運転後のセル電圧は停止前と同じで
あった。負荷を切る直前の空気出口ガスから１％程度の
H2が検知された。Normally, the air flow rate and the fuel flow rate are interlocked and controlled so that the air utilization rate and the fuel utilization rate are kept constant in proportion to the current density. However, while in this embodiment, keeping the fuel utilization rate to 75% (effective area of the electrode as described above is a case of 100 cm 2, corresponding to 15A of current) current density 150 mA / cm 2 was maintained, the air After decreasing only the flow rate and increasing the air utilization rate to 120%, after 5 minutes the load and the supply of reaction gas were cut off and the operation was stopped.
Maintained at 75%. The cell voltage after the restart was the same as before the shutdown. About 1% from the air outlet gas just before turning off the load
H 2 was detected.
このように、空気出口ガスから水素が検知されること
は、空気極から水素発生が起こっていることを示すもの
であり、従来の停止モードでは起こり得ない現象であ
る。Thus, detection of hydrogen from the air outlet gas indicates that hydrogen is being generated from the air electrode, which is a phenomenon that cannot occur in the conventional stop mode.
実施例２ 205℃、150mA/cm2常圧で動作中のリン酸型燃料電池の
21セルスタックの空気の供給を完全に遮断した後、（空
気利用率は当然100％以上）１分後負荷及び反応ガスの
供給を切って運転を停止したこのときの燃料利用率は75
％を維持した。再運転後のセル電圧は停止前と同じであ
った。負荷を切る直前の空気出口ガスから４％程度のH2
が検知された。Example 2 Example of phosphoric acid fuel cell operating at 205 ° C. and 150 mA / cm 2 normal pressure
After completely shutting off the air supply to the 21-cell stack (air usage rate is 100% or more), after 1 minute the load and the supply of reaction gas were cut off to stop the operation.
% Maintained. The cell voltage after the restart was the same as before the shutdown. About 4% H 2 from the air outlet gas just before the load is removed
Was detected.
この発明の方法によれば、不活性ガスを用いることな
く正極の電位が高くなるのを防止して運転を停止させる
ことができる。また、停止中に不活性ガスを流す必要も
ない。これは正極で発生させたH2で正極の電位を低く保
つことができるからである。さらに再運転の際にも必ず
しも不活性ガスを反応ガスに先じて流す必要はない。こ
れは正極に水素がたまっているといっても酸素がほとん
ど残っていないので、再運転の際すぐに空気を流しても
正極にたまっている水素は、爆発限界に至ることなくそ
のまま出口側へ排出されてしまうからである。なお、酸
化剤の酸素利用率は85％以上で水素発生しうることは先
の学会（ISE）の発表で明かであり、酸素利用率を上げ
てからの経過時間と電流密度から正極での発生H2量を制
御することができる。According to the method of the present invention, it is possible to prevent the potential of the positive electrode from increasing and to stop the operation without using an inert gas. Further, it is not necessary to flow the inert gas during the stop. This is because H 2 generated at the positive electrode can keep the positive electrode potential low. Further, it is not always necessary to flow the inert gas prior to the reaction gas at the time of restarting. Even if hydrogen is accumulated in the positive electrode, almost no oxygen remains.Therefore, even if air is immediately flown during restart, the hydrogen accumulated in the positive electrode does not reach the explosion limit and goes to the outlet side as it is. Because it will be discharged. In addition, it is clear from the previous academic conference (ISE) that hydrogen can be generated when the oxygen utilization rate of the oxidant is 85% or more, and the generation rate at the positive electrode can be determined from the elapsed time after increasing the oxygen utilization rate and the current density. The amount of H 2 can be controlled.
なお、この発明はリン酸型燃料電池に限らず固体高分
子電解質型燃料電池（SPFC）、硫酸型燃料電池、アルカ
リ型燃料電池など貴金属を触媒として用いる燃料電池に
共通して用いることができる。The present invention is not limited to the phosphoric acid type fuel cell, and can be commonly used for solid polyelectrolyte type fuel cells (SPFC), sulfuric acid type fuel cells, alkaline type fuel cells, and other fuel cells using precious metals as catalysts.
［発明の効果］ 以上のようにこの発明によれば、各々が正極と負極と
を有する複数個の燃料電池が、電気的に直列に接続され
た燃料電池積層体を有し、酸化剤が各燃料電池の正極に
接する空気流路へ供給され、燃料が各燃料電池の負極に
接する燃料流路へ供給されて発電し、外部負荷を繋いで
外部負荷および燃料電池に電流を流して運転される燃料
電池において、外部負荷を繋いで外部負荷および燃料電
池に電流を流した状態で、燃料の水素利用率を90％以下
に保ち、かつ、酸化剤の酸素利用率を85％以上に上げて
正極内で水素を発生させた後、外部負荷を切って運転を
停止するようにしたので、補機や不活性ガスを用いずに
正極の電位が高くなるのを防止することのできる燃料電
池の停止方法が得られ、装置が安価にできる効果があ
る。[Effects of the Invention] As described above, according to the present invention, a plurality of fuel cells each having a positive electrode and a negative electrode have a fuel cell stack electrically connected in series, and the oxidizer is It is supplied to the air flow path in contact with the positive electrode of the fuel cell, and the fuel is supplied to the fuel flow path in contact with the negative electrode of each fuel cell to generate electric power. By connecting an external load, a current is supplied to the external load and the fuel cell to operate. In a fuel cell, with the external load connected and an electric current flowing through the external load and the fuel cell, the hydrogen utilization rate of the fuel is kept below 90%, and the oxygen utilization rate of the oxidizer is raised to above 85%. After generating hydrogen inside, the external load is turned off to stop the operation, so that the potential of the positive electrode can be prevented from increasing without using auxiliary machinery or inert gas. There is an effect that a method can be obtained and the apparatus can be inexpensive.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 堀内 弘志 兵庫県神戸市兵庫区和田崎町１丁目１番 ２号 三菱電機株式会社神戸製作所内 (56)参考文献 特開 昭59−211970（ＪＰ，Ａ) 特開 昭62−150665（ＪＰ，Ａ) 特開 昭60−177565（ＪＰ，Ａ) 特公 昭60−10425（ＪＰ，Ｂ２) ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Horiuchi 1-2-2 Wadazaki-cho, Hyogo-ku, Kobe-shi, Hyogo Mitsubishi Electric Corporation Kobe Works (56) Reference JP-A-59-211970 (JP, A) JP 62-150665 (JP, A) JP 60-177565 (JP, A) JP 60-60425 (JP, B2)
Claims (1)
電池が、電気的に直列に接続された燃料電池積層体を有
し、 酸化剤が前記各燃料電池の正極に接する空気流路へ供給
され、燃料が前記各燃料電池の負極に接する燃料流路へ
供給されて発電し、 外部負荷を繋いで前記外部負荷および前記燃料電池に電
流を流して運転される燃料電池において、 前記外部負荷を繋いで前記外部負荷および前記燃料電池
に電流を流した状態で、前記燃料の水素利用率を90％以
下に保ち、かつ、前記酸化剤の酸素利用率を85％以上に
上げて前記正極内で前記水素を発生させた後、前記外部
負荷を切って運転を停止することを特徴とする燃料電池
の停止方法。1. An air flow path in which a plurality of fuel cells each having a positive electrode and a negative electrode have a fuel cell stack electrically connected in series, and an oxidant is in contact with the positive electrode of each fuel cell. Is supplied to the fuel flow path in contact with the negative electrode of each of the fuel cells to generate electric power, which is operated by connecting an external load and applying a current to the external load and the fuel cell. With the load connected to the external load and the current flowing through the fuel cell, the hydrogen utilization rate of the fuel is maintained at 90% or less, and the oxygen utilization rate of the oxidant is increased to 85% or more to increase the positive electrode. A method of stopping a fuel cell, wherein the operation is stopped by turning off the external load after the hydrogen is generated inside.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1333940A JP2542096B2 (en) | 1989-12-22 | 1989-12-22 | How to stop the fuel cell |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1333940A JP2542096B2 (en) | 1989-12-22 | 1989-12-22 | How to stop the fuel cell |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03194863A JPH03194863A (en) | 1991-08-26 |
| JP2542096B2 true JP2542096B2 (en) | 1996-10-09 |
Family
ID=18271678
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1333940A Expired - Fee Related JP2542096B2 (en) | 1989-12-22 | 1989-12-22 | How to stop the fuel cell |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2542096B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7943261B2 (en) | 2002-10-31 | 2011-05-17 | Panasonic Corporation | Method of operating fuel cell system and fuel cell system |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ATE221259T1 (en) * | 1996-06-10 | 2002-08-15 | Siemens Ag | METHOD FOR OPERATING A PEM FUEL CELL SYSTEM |
| JP4632501B2 (en) * | 2000-09-11 | 2011-02-16 | 大阪瓦斯株式会社 | How to stop and store fuel cells |
| JP4872181B2 (en) * | 2003-09-10 | 2012-02-08 | パナソニック株式会社 | Fuel cell system and operation method thereof |
| US7479337B2 (en) * | 2003-09-17 | 2009-01-20 | General Motors Corporation | Fuel cell shutdown and startup using a cathode recycle loop |
| JP2008071642A (en) * | 2006-09-14 | 2008-03-27 | Toshiba Fuel Cell Power Systems Corp | Solid polymer electrolyte fuel cell system and its operation method |
-
1989
- 1989-12-22 JP JP1333940A patent/JP2542096B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7943261B2 (en) | 2002-10-31 | 2011-05-17 | Panasonic Corporation | Method of operating fuel cell system and fuel cell system |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03194863A (en) | 1991-08-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JPH06333586A (en) | Method for stopping fuel cell | |
| CN100481596C (en) | Fuel cell power generating equipment driving method and fuel cell power generating equipment | |
| JPH0927336A (en) | Fuel cell stack diagnostic method | |
| JP2010027580A (en) | Fuel cell system | |
| JP2005507542A (en) | High fuel utilization in the fuel cell | |
| US7148654B2 (en) | Method and apparatus for monitoring fuel cell voltages | |
| JP2542096B2 (en) | How to stop the fuel cell | |
| JPH0233866A (en) | Operation discontinuing method for fuel cell | |
| JP2011076818A (en) | Fuel battery power generation system and method for operating the same | |
| JP3536645B2 (en) | Fuel cell operation control method | |
| JP2009070788A (en) | Fuel supply control method and fuel cell device utilizing the method | |
| WO2006077461A2 (en) | Fuel cell systems and control methods | |
| JP6543671B2 (en) | Fuel cell output inspection method | |
| JPH0955219A (en) | Fuel cell power generating device and operation method | |
| JPH05251102A (en) | Phospholic acid type fuel cell power generating plant | |
| JPH01128362A (en) | Operating method for fuel cell | |
| JPH01200567A (en) | Power generation system of fuel cell | |
| CN112956059B (en) | Method and system for operating an electrochemical fuel cell stack with improved performance recovery | |
| JP2931372B2 (en) | Operating method of fuel cell power generation system | |
| JPH09120830A (en) | Starting method for fuel cell power-generating device | |
| US20050089729A1 (en) | Technique and apparatus to control the response of a fuel cell system to load transients | |
| US11158873B2 (en) | Control device for fuel cell system | |
| JPH0439189B2 (en) | ||
| JPH04174975A (en) | Multilayer fuel cell | |
| JPH05335026A (en) | Phosphoric acid fuel cell and method for stopping its operation |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20070725 Year of fee payment: 11 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20080725 Year of fee payment: 12 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090725 Year of fee payment: 13 |
|
| LAPS | Cancellation because of no payment of annual fees |