JP2005100952A - Fuel cell system - Google Patents

Fuel cell system Download PDF

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JP2005100952A
JP2005100952A JP2004214418A JP2004214418A JP2005100952A JP 2005100952 A JP2005100952 A JP 2005100952A JP 2004214418 A JP2004214418 A JP 2004214418A JP 2004214418 A JP2004214418 A JP 2004214418A JP 2005100952 A JP2005100952 A JP 2005100952A
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current
fuel cell
fuel
hydrogen
measured
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JP4639680B2 (en
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Tomonori Imamura
朋範 今村
Toshiyuki Kawai
利幸 河合
Shinya Sakaguchi
信也 坂口
Hidetsugu Izuhara
英嗣 伊豆原
Hideki Kashiwagi
秀樹 柏木
Tetsuo Kikuchi
哲郎 菊地
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Denso Corp
Soken Inc
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Denso Corp
Nippon Soken Inc
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Priority to US10/931,981 priority patent/US7670700B2/en
Priority to DE102004042780A priority patent/DE102004042780A1/en
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    • 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

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Abstract

<P>PROBLEM TO BE SOLVED: To accurately diagnose causes for decreasing the output of a fuel cell. <P>SOLUTION: Current flowing through a part that is easily dried in the fuel cell 10 is measured by current measuring means 132, 133, 164, 165, 172, and 173. When the current is less than a specified current value, the fuel cell 10 is diagnosed to be in a dry state. Additionally, current flowing through the part in which moisture tends to become excessive in the fuel cell 10 and hydrogen easily lacks is measured by current measuring means 134, 166, and 174. When the current is less than a specified current value and a decrease speed in the current is less than a specified decrease speed, the fuel cell is diagnosed to have surplus moisture. When the current is less than the specified current value and the decrease speed of current is equal to or more than the specified decrease speed, the amount of supply of hydrogen to the fuel cell is diagnosed to be in shortage. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、水素と酸素との電気化学反応により電気エネルギを発生させる燃料電池を備える燃料電池システムに関するもので、車両、船舶及びポータブル発電機等の移動体用発電機、或いは家庭用発電機に適用して有効である。   The present invention relates to a fuel cell system including a fuel cell that generates electric energy by an electrochemical reaction between hydrogen and oxygen. The present invention relates to a generator for a mobile body such as a vehicle, a ship, and a portable generator, or a household generator. It is effective to apply.

水素と酸素との電気化学反応を利用して発電を行う燃料電池システムでは、水分が不足すると電解質膜が乾燥して電池の出力が低下し、一方、水分が過剰になると電極が水に覆われてガスの透過が阻害され、電池の出力が低下する。したがって、電解質膜の保水状態や電極の濡れ状態を的確に診断して、保水状態や濡れ状態を適正に制御する必要がある。また、反応ガスの供給量が不足した場合も電池の出力が低下するため、反応ガス不足を適確に診断して、反応ガス供給量を適正に制御する必要がある。   In a fuel cell system that generates electricity using an electrochemical reaction between hydrogen and oxygen, the electrolyte membrane dries and the battery output decreases when moisture is insufficient, while the electrode is covered with water when moisture is excessive. As a result, gas permeation is hindered and the output of the battery is reduced. Therefore, it is necessary to accurately diagnose the water retention state of the electrolyte membrane and the wet state of the electrode and to appropriately control the water retention state and the wet state. Further, since the output of the battery is lowered even when the supply amount of the reaction gas is insufficient, it is necessary to appropriately diagnose the lack of the reaction gas and appropriately control the reaction gas supply amount.

ところで、燃料電池の運転状態を診断するには、セル電圧の低下から異常状態を診断する方法が考えられる。また、燃料電池内の電流分布から反応ガスの過不足を診断し、反応ガス流量もしくは負荷電流を制御して燃料電池の破壊を防止するようにしたものも提案されている（例えば、特許文献１参照）。
特開平９−２５９９１３号公報 By the way, in order to diagnose the operating state of the fuel cell, a method of diagnosing an abnormal state from a decrease in cell voltage can be considered. In addition, there has been proposed one that diagnoses the excess or deficiency of the reaction gas from the current distribution in the fuel cell and controls the reaction gas flow rate or load current to prevent the destruction of the fuel cell (for example, Patent Document 1). reference).
JP-A-9-259913

しかしながら、セル電圧の低下から異常状態を診断する方法の場合、電解質膜の乾燥、過剰な水による反応阻害、および反応ガスの供給不足のいずれによってもセル電圧が低下するため、燃料電池の出力低下要因を特定することができず、したがって出力低下要因に応じた適確な制御が行えないといった問題が発生する。   However, in the case of a method of diagnosing an abnormal state from a decrease in cell voltage, the cell voltage decreases due to drying of the electrolyte membrane, reaction inhibition due to excessive water, and insufficient supply of reaction gas, so the output of the fuel cell decreases. There is a problem that the factor cannot be specified, and therefore, it is not possible to perform accurate control according to the output reduction factor.

一方、特許文献１に記載のシステムでは、反応ガスの過不足のみを診断しているため、出力低下要因を適確に診断することは不可能である。そのため、反応ガス流量以外の水過剰状態や電解質膜の乾燥状態を区別することができず、したがって出力低下要因に応じた適確な制御が行えないといった問題が発生する。   On the other hand, in the system described in Patent Document 1, since only the excess or deficiency of the reaction gas is diagnosed, it is impossible to accurately diagnose the output reduction factor. For this reason, it is not possible to distinguish between the excess water state other than the reaction gas flow rate and the dry state of the electrolyte membrane, and thus there arises a problem that accurate control according to the output reduction factor cannot be performed.

本発明は上記点に鑑みて、燃料電池の出力低下要因を適確に診断可能にすることを目的とする。   In view of the above points, an object of the present invention is to enable accurate diagnosis of a fuel cell output reduction factor.

上記目的を達成するため、請求項１に記載の発明では、酸化剤ガスと燃料ガスとを電気化学反応させて電気エネルギを発生させる燃料電池（１０）と、燃料電池内において乾燥しやすい部位（Ｂ、Ｃ）を流れる電流を測定する電流測定手段（１３２、１３３、１５１、１５２、１６１、１６２、１６４、１６５、１７２、１７３）と、電流測定手段で測定された電流値に基づいて燃料電池内部の乾燥状態を診断する診断手段（４０）とを備えることを特徴とする。これによると、燃料電池が乾燥した際には、それを適確に診断することができる。   In order to achieve the above object, according to the first aspect of the present invention, a fuel cell (10) that generates an electrical energy by electrochemical reaction of an oxidant gas and a fuel gas, and a portion that is easily dried in the fuel cell ( B, C) Current measuring means (132, 133, 151, 152, 161, 162, 164, 165, 172, 173) for measuring the current flowing through the fuel cell based on the current value measured by the current measuring means And a diagnostic means (40) for diagnosing the internal dry state. According to this, when the fuel cell is dried, it can be accurately diagnosed.

具体的には、請求項２に記載の発明のように、診断手段は、電流測定手段にて測定した電流が所定電流値未満のときは、燃料電池が乾燥状態であると診断することができる。さらに、請求項３に記載の発明のように、電流測定手段で測定された電流値と、予め設定された所定電流値との差に基づいて燃料電池内部の乾燥状態の程度を診断することができる。   Specifically, as in the invention described in claim 2, the diagnosis means can diagnose that the fuel cell is in a dry state when the current measured by the current measurement means is less than a predetermined current value. . Furthermore, as in the third aspect of the invention, the degree of dryness inside the fuel cell can be diagnosed based on the difference between the current value measured by the current measuring means and a predetermined current value set in advance. it can.

請求項４に記載の発明では、燃料電池の電圧を測定する電圧測定手段（１２）を備え、診断手段は、電圧測定手段で測定された電圧値と電流測定手段で測定された電流値とに基づいて、燃料電池（１０）内において乾燥しやすい部位の抵抗値を演算し、抵抗値に基づいて燃料電池内部の乾燥状態を診断することを特徴とする。これによっても、燃料電池が乾燥した際には、それを適確に診断することができる。   According to a fourth aspect of the present invention, the voltage measuring means (12) for measuring the voltage of the fuel cell is provided, and the diagnostic means is configured to convert the voltage value measured by the voltage measuring means and the current value measured by the current measuring means. Based on this, a resistance value of a portion that is easily dried in the fuel cell (10) is calculated, and a dry state inside the fuel cell is diagnosed based on the resistance value. This also makes it possible to accurately diagnose when the fuel cell has dried.

因みに、請求項１に記載の発明の実施に際しては、請求項５に記載の発明のように、燃料電池（１０）は、電解質膜の両側に一対の電極が配置された電解質・電極接合体（１００）と、電解質・電極接合体の外側に配置されるとともに酸化剤ガスの流路となる酸化剤ガス流路（１１３）が形成された第１セパレータ（１１０）と、電解質・電極接合体の外側に配置されるとともに燃料ガスの流路となる燃料ガス流路（１２３）が形成された第２セパレータ（１２０）とを備え、電流測定手段（１３２、１５１、１６１、１６４、１７２）は、酸化剤ガス流路における酸化剤ガスの出口部（１１２）よりも酸化剤ガスの入口部（１１１）に近い位置で電流を測定するようにしてもよいし、請求項６に記載の発明のように、電流測定手段（１３３、１５２、１６２、１６５、１７３）は、燃料ガス流路における燃料ガスの出口部（１２２）よりも燃料ガスの入口部（１２１）に近い位置で電流を測定するようにしてもよい。   Incidentally, in carrying out the invention according to claim 1, as in the invention according to claim 5, the fuel cell (10) includes an electrolyte-electrode assembly in which a pair of electrodes are arranged on both sides of the electrolyte membrane ( 100), a first separator (110) disposed outside the electrolyte / electrode assembly and having an oxidant gas flow path (113) serving as a flow path for the oxidant gas, and the electrolyte / electrode assembly A second separator (120) disposed outside and formed with a fuel gas flow path (123) serving as a fuel gas flow path, and the current measuring means (132, 151, 161, 164, 172), The current may be measured at a position closer to the oxidant gas inlet (111) than to the oxidant gas outlet (112) in the oxidant gas flow path. Current measuring means (133 152,162,165,173) may be adapted to measure a current at a position close to the inlet portion of the fuel gas (121) than the outlet portion of the fuel gas in the fuel gas passage (122).

請求項７に記載の発明では、酸化剤ガスと燃料ガスとを電気化学反応させて電気エネルギを発生させる燃料電池（１０）と、燃料電池（１０）内において液滴が滞留しやすい部位（Ｄ）を流れる電流を測定する電流測定手段（１３４、１５３、１６３、１６６、１７４）と、電流測定手段にて測定した電流値に基づいて燃料電池の水分過剰状態を診断する診断手段（４０）を備えることを特徴とする。これによると、燃料電池内部が水分過剰となった際には、それを適確に診断することができる。   In the seventh aspect of the invention, the fuel cell (10) that generates an electric energy by electrochemically reacting the oxidant gas and the fuel gas, and the portion where the droplets are likely to stay in the fuel cell (10) (D ) Current measuring means (134, 153, 163, 166, 174) for measuring the current flowing through the current), and diagnostic means (40) for diagnosing the excess water state of the fuel cell based on the current value measured by the current measuring means. It is characterized by providing. According to this, when the moisture inside the fuel cell becomes excessive, it can be diagnosed accurately.

具体的には、請求項８に記載の発明のように、診断手段は、電流測定手段にて測定した電流が所定電流値未満のときは、燃料電池が水分過剰状態であると診断することができる。さらに、請求項９に記載の発明のように、電流測定手段で測定された電流値と、予め設定された所定電流値との差に基づいて燃料電池（１０）内部の水分過剰状態の程度を診断することができる。   Specifically, as in the invention described in claim 8, the diagnosis means can diagnose that the fuel cell is in an excessive water state when the current measured by the current measurement means is less than a predetermined current value. it can. Further, as in the invention described in claim 9, the degree of excess moisture in the fuel cell (10) is determined based on the difference between the current value measured by the current measuring means and a predetermined current value set in advance. Can be diagnosed.

請求項１０に記載の発明では、燃料電池の電圧を測定する電圧測定手段（１２）を備え、診断手段は、電圧測定手段で測定された電圧値と電流測定手段で測定された電流値とに基づいて、燃料電池（１０）内において水分過剰となりやすい部位の抵抗値を演算し、抵抗値に基づいて燃料電池内部の水分過剰状態を診断することを特徴とする。これによっても、燃料電池内部が水分過剰となった際には、それを適確に診断することができる。   In the tenth aspect of the present invention, the voltage measuring means (12) for measuring the voltage of the fuel cell is provided, and the diagnostic means is configured to obtain a voltage value measured by the voltage measuring means and a current value measured by the current measuring means. Based on this, a resistance value of a portion that tends to be excessive in the fuel cell (10) is calculated, and an excessive water state inside the fuel cell is diagnosed based on the resistance value. This also makes it possible to accurately diagnose when the water content in the fuel cell becomes excessive.

請求項１１に記載の発明では、酸化剤ガスと燃料ガスとの電気化学反応により電気エネルギを発生させる燃料電池（１０）と、燃料電池（１０）内において燃料ガスが不足しやすい部位（Ｄ）を流れる電流を測定する電流測定手段（１３４、１５３、１６３、１６６、１７４）と、電流測定手段にて測定した電流値に基づいて燃料電池の燃料ガスの不足状態を診断する診断手段（４０）を備えることを特徴とする。これによると、燃料電池への水素の供給量が不足した際には、それを適確に診断することができる。   In the invention described in claim 11, the fuel cell (10) that generates electric energy by the electrochemical reaction between the oxidant gas and the fuel gas, and the portion (D) where the fuel gas tends to be insufficient in the fuel cell (10). Current measuring means (134, 153, 163, 166, 174) for measuring the current flowing through the fuel cell and diagnostic means (40) for diagnosing a shortage of fuel gas in the fuel cell based on the current value measured by the current measuring means It is characterized by providing. According to this, when the supply amount of hydrogen to the fuel cell is insufficient, it can be accurately diagnosed.

具体的には、請求項１２に記載の発明のように、診断手段（４０）は、電流測定手段にて測定した電流が所定電流値未満で、且つ電流測定手段にて測定した電流の低下速度が所定低下速度以上であるときは、燃料電池への燃料ガスの供給量が不足していると診断することができる。   Specifically, as in the invention described in claim 12, the diagnosis means (40) is configured such that the current measured by the current measurement means is less than a predetermined current value and the rate of decrease in the current measured by the current measurement means. Can be diagnosed as insufficient fuel gas supply to the fuel cell.

請求項１３に記載の発明では、酸化剤ガスと燃料ガスとの電気化学反応により電気エネルギを発生させる燃料電池（１０）と、燃料電池（１０）内において水分過剰になりやすく且つ燃料ガスが不足しやすい部位（Ｄ）を流れる電流を測定する電流測定手段（１３４、１５３、１６３）と、電流測定手段で測定した電流の低下速度に基づいて、燃料電池の水分過剰と燃料電池の燃料ガス不足とを区別して診断する診断手段（４０）とを備えることを特徴とする。   In the invention according to claim 13, the fuel cell (10) that generates electric energy by the electrochemical reaction between the oxidant gas and the fuel gas, the water tends to be excessive in the fuel cell (10), and the fuel gas is insufficient. Based on the current measurement means (134, 153, 163) for measuring the current flowing through the part (D) that is easy to perform, and the rate of decrease in the current measured by the current measurement means, the fuel cell has excessive moisture and the fuel cell has insufficient fuel gas. And a diagnostic means (40) for making a distinction and making a diagnosis.

これによると、燃料電池が水分過剰となった際には、それを適確に診断することができるとともに、燃料電池への水素の供給量が不足した際には、それを適確に診断することができる。また、電流の低下速度によって燃料電池の出力低下要因が水分過剰であるか水素供給不足であるかを特定することができ、したがって出力低下要因に応じた適確な制御を行うことができる。   According to this, when the fuel cell becomes excessive in water, it can be diagnosed accurately, and when the supply amount of hydrogen to the fuel cell is insufficient, it is diagnosed accurately. be able to. In addition, it is possible to specify whether the output reduction factor of the fuel cell is excessive water or insufficient hydrogen supply based on the current decrease rate, and therefore it is possible to perform accurate control according to the output decrease factor.

具体的には、請求項１４に記載の発明では、診断手段は、電流測定手段にて測定した電流が所定電流値未満で、且つ電流測定手段にて測定した電流の低下速度が所定低下速度未満であるときは、燃料電池の水分が過剰になっていると診断し、電流測定手段にて測定した電流が所定電流値未満で、且つ電流測定手段にて測定した電流の低下速度が所定低下速度以上であるときは、燃料電池への燃料ガスの供給量が不足していると診断することができる。   Specifically, in the invention described in claim 14, the diagnostic means has a current measured by the current measuring means that is less than a predetermined current value, and a current decrease rate measured by the current measuring means is less than a predetermined decrease speed. When the fuel cell is in excess of water, the current measured by the current measuring means is less than the predetermined current value, and the current decreasing speed measured by the current measuring means is the predetermined decreasing speed. When it is above, it can be diagnosed that the amount of fuel gas supplied to the fuel cell is insufficient.

因みに、請求項７ないし１４のいずれか１つに記載の発明の実施に際しては、請求項１５に記載の発明のように、燃料電池（１０）は、電解質膜の両側に一対の電極が配置された電解質・電極接合体（１００）と、電解質・電極接合体の外側に配置されるとともに酸化ガスの流路となる酸化ガス流路（１１３）が形成された第１セパレータ（１１０）と、電解質・電極接合体の外側に配置されるとともに燃料ガスの流路となる燃料ガス流路（１２３）が形成された第２セパレータ（１２０）とを備え、電流測定手段（１３４、１５３、１６３、１６６、１７４）は、燃料ガス流路における燃料ガスの入口部（１２１）よりも燃料ガスの出口部（１２２）に近い位置で電流を測定するようにしてもよい。   Incidentally, in carrying out the invention according to any one of claims 7 to 14, as in the invention according to claim 15, the fuel cell (10) has a pair of electrodes disposed on both sides of the electrolyte membrane. An electrolyte / electrode assembly (100), a first separator (110) formed outside the electrolyte / electrode assembly and having an oxidizing gas channel (113) serving as an oxidizing gas channel, and an electrolyte A second separator (120) disposed outside the electrode assembly and having a fuel gas flow path (123) serving as a fuel gas flow path; and current measuring means (134, 153, 163, 166) 174) may measure the current at a position closer to the fuel gas outlet (122) than the fuel gas inlet (121) in the fuel gas flow path.

なお、上記各手段の括弧内の符号は、後述する実施形態に記載の具体的手段との対応関係を示すものである。   In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

（第１実施形態）
図１は第１実施形態に係る燃料電池システムを示す模式図で、この燃料電池システムは例えば電気自動車に適用される。 (First embodiment)
FIG. 1 is a schematic diagram showing a fuel cell system according to the first embodiment, and this fuel cell system is applied to, for example, an electric vehicle.

図１に示すように、本実施形態の燃料電池システムは、水素と酸素との電気化学反応を利用して電力を発生する燃料電池１０を備えている。この燃料電池１０は、電気負荷１１や２次電池（図示せず）等の電気機器に電力を供給するものである。因みに、電気自動車の場合、車両走行駆動源としての電動モータが電気負荷１１に相当する。   As shown in FIG. 1, the fuel cell system of this embodiment includes a fuel cell 10 that generates electric power by utilizing an electrochemical reaction between hydrogen and oxygen. The fuel cell 10 supplies electric power to electric devices such as an electric load 11 and a secondary battery (not shown). Incidentally, in the case of an electric vehicle, an electric motor as a vehicle driving source corresponds to the electric load 11.

本実施形態では燃料電池１０として固体高分子電解質型燃料電池を用いており、基本単位となる燃料電池セルが複数個積層され、且つ電気的に直列接続されている。燃料電池１０では、以下の水素と酸素の電気化学反応が起こり電気エネルギが発生する。   In the present embodiment, a solid polymer electrolyte fuel cell is used as the fuel cell 10, and a plurality of fuel cells serving as basic units are stacked and electrically connected in series. In the fuel cell 10, the following electrochemical reaction between hydrogen and oxygen occurs to generate electric energy.

（負極側）Ｈ2→２Ｈ+＋２ｅ-
（正極側）２Ｈ+＋１／２Ｏ2＋２ｅ-→Ｈ2Ｏ
そして、各セル毎の出力電圧を検出するセルモニタ１２が設けられ、セルモニタ１２で検出したセル電圧信号が後述する制御部４０に入力されるようになっている。 (Negative electrode side) H 2 → 2H + + 2e −
(Positive electrode side) 2H + + 1 / 2O 2 + 2e − → H 2 O
A cell monitor 12 for detecting an output voltage for each cell is provided, and a cell voltage signal detected by the cell monitor 12 is input to the control unit 40 described later.

燃料電池システムには、燃料電池１０の空気極（正極）側に空気（酸素）を供給するための空気流路２０と、燃料電池１０の水素極（負極）側に水素を供給するための水素流路３０が設けられている。なお、空気は本発明の酸化ガスに相当し、水素は本発明の燃料ガスに相当する。   The fuel cell system includes an air flow path 20 for supplying air (oxygen) to the air electrode (positive electrode) side of the fuel cell 10 and hydrogen for supplying hydrogen to the hydrogen electrode (negative electrode) side of the fuel cell 10. A flow path 30 is provided. Air corresponds to the oxidizing gas of the present invention, and hydrogen corresponds to the fuel gas of the present invention.

空気流路２０の最上流部には、大気中から吸入した空気を燃料電池１０に圧送するための空気ポンプ２１が設けられ、空気流路２０における空気ポンプ２１と燃料電池１０との間には、空気への加湿を行う加湿器２２が設けられ、空気流路２０における燃料電池１０の下流側には、燃料電池１０に供給される空気の圧力を調整するための空気調圧弁２３が設けられている。   An air pump 21 is provided at the most upstream portion of the air flow path 20 to pump air sucked from the atmosphere to the fuel cell 10. Between the air pump 21 and the fuel cell 10 in the air flow path 20. A humidifier 22 for humidifying the air is provided, and an air pressure regulating valve 23 for adjusting the pressure of the air supplied to the fuel cell 10 is provided on the downstream side of the fuel cell 10 in the air flow path 20. ing.

水素流路３０の最上流部には、水素が充填された水素ボンベ３１が設けられ、水素流路３０における水素ボンベ３１と燃料電池１０との間には、燃料電池１０に供給される水素の圧力を調整するための水素調圧弁３２と、水素への加湿を行う加湿器３３が設けられている。   A hydrogen cylinder 31 filled with hydrogen is provided in the uppermost stream portion of the hydrogen flow path 30, and hydrogen supplied to the fuel cell 10 is interposed between the hydrogen cylinder 31 and the fuel cell 10 in the hydrogen flow path 30. A hydrogen pressure regulating valve 32 for adjusting the pressure and a humidifier 33 for humidifying the hydrogen are provided.

水素流路３０における燃料電池１０の下流側は、水素調圧弁３２の下流側に接続されて水素流路３０が閉ループに構成されており、これにより水素流路３０内で水素を循環させて、燃料電池１０での未使用水素を燃料電池１０に再供給するようにしている。そして、水素流路３０における燃料電池１０の下流側には、水素流路３０内で水素を循環させるための水素ポンプ３４が設けられている。   The downstream side of the fuel cell 10 in the hydrogen flow path 30 is connected to the downstream side of the hydrogen pressure regulating valve 32 so that the hydrogen flow path 30 is configured in a closed loop, thereby circulating hydrogen in the hydrogen flow path 30, Unused hydrogen in the fuel cell 10 is resupplied to the fuel cell 10. A hydrogen pump 34 for circulating hydrogen in the hydrogen channel 30 is provided on the downstream side of the fuel cell 10 in the hydrogen channel 30.

制御部（ＥＣＵ）４０は、本発明の診断手段に相当し、ＣＰＵ、ＲＯＭ、ＲＡＭ等からなる周知のマイクロコンピュータとその周辺回路にて構成されている。そして、制御部４０には、セルモニタ１２からのセル電圧信号や後述する電流センサからの信号が入力される。また、制御部４０は、演算結果に基づいて、空気ポンプ２１、加湿器２２、３３、空気調圧弁２３、水素調圧弁３２、水素ポンプ３４に制御信号を出力する。   The control unit (ECU) 40 corresponds to the diagnostic means of the present invention, and is composed of a well-known microcomputer comprising a CPU, ROM, RAM, etc. and its peripheral circuits. The control unit 40 receives a cell voltage signal from the cell monitor 12 and a signal from a current sensor described later. Further, the control unit 40 outputs a control signal to the air pump 21, the humidifiers 22, 33, the air pressure regulating valve 23, the hydrogen pressure regulating valve 32, and the hydrogen pump 34 based on the calculation result.

図２は燃料電池１０の単セルを示す模式的な斜視図であり、燃料電池１０の単セルは、電解質膜の両側面に電極が配置されたＭＥＡ（Membrane Electrode Assembly：電解質・電極接合体）１００と、このＭＥＡ１００を挟持する空気側セパレータ１１０および水素側セパレータ１２０で構成されている。また、水素側セパレータ１２０に隣接して−極の集電板１３０が配置されている。因みに、空気側セパレータ１１０は＋極の集電板を兼ねている。   FIG. 2 is a schematic perspective view showing a single cell of the fuel cell 10, and the single cell of the fuel cell 10 is an MEA (Membrane Electrode Assembly) in which electrodes are arranged on both sides of the electrolyte membrane. 100, and an air-side separator 110 and a hydrogen-side separator 120 that sandwich the MEA 100. Further, a negative electrode current collector plate 130 is disposed adjacent to the hydrogen side separator 120. Incidentally, the air-side separator 110 also serves as a positive electrode current collector plate.

図３は図２の右側から見た空気側セパレータ１１０の透視図であり、空気側セパレータ１１０は、空気流路２０に接続される空気入口部１１１および空気出口部１１２と、空気入口部１１１から空気出口部１１２に向かって空気を流すための空気流路溝１１３とを備えている。なお、空気側セパレータ１１０は本発明の第１セパレータに相当し、空気流路溝１１３は本発明の酸化ガス流路に相当し、空気入口部１１１は本発明の酸化ガスの入口部に相当し、空気出口部１１２は本発明の酸化ガスの出口部に相当する。   3 is a perspective view of the air-side separator 110 viewed from the right side of FIG. 2. The air-side separator 110 includes an air inlet portion 111 and an air outlet portion 112 connected to the air flow path 20, and an air inlet portion 111. And an air flow path groove 113 for flowing air toward the air outlet portion 112. The air-side separator 110 corresponds to the first separator of the present invention, the air flow path groove 113 corresponds to the oxidizing gas flow path of the present invention, and the air inlet 111 corresponds to the oxidizing gas inlet of the present invention. The air outlet 112 corresponds to the oxidizing gas outlet of the present invention.

図４は図２の右側から見た水素側セパレータ１２０の透視図であり、水素側セパレータ１２０は、水素流路３０に接続される水素入口部１２１および水素出口部１２２と、水素入口部１２１から水素出口部１２２に向かって水素を流すための水素流路溝１２３とを備えている。なお、水素側セパレータ１２０は本発明の第２セパレータに相当し、水素流路溝１２３は本発明の燃料ガス流路に相当し、水素入口部１２１は本発明の燃料ガスの入口部に相当し、水素出口部１２２は本発明の燃料ガスの出口部に相当する。   4 is a perspective view of the hydrogen side separator 120 as viewed from the right side of FIG. 2. The hydrogen side separator 120 includes a hydrogen inlet part 121 and a hydrogen outlet part 122 connected to the hydrogen flow path 30, and a hydrogen inlet part 121. And a hydrogen passage groove 123 for flowing hydrogen toward the hydrogen outlet portion 122. The hydrogen separator 120 corresponds to the second separator of the present invention, the hydrogen channel groove 123 corresponds to the fuel gas channel of the present invention, and the hydrogen inlet 121 corresponds to the fuel gas inlet of the present invention. The hydrogen outlet 122 corresponds to the fuel gas outlet of the present invention.

図５は図２における−極側の要部の拡大図、図６は図５のＡ−Ａ線に沿う断面図である。図２、図５、図６に示すように、集電板１３０は、主集電板１３１と３つの副集電板１３２〜１３４に分割されている。この主集電板１３１および３つの副集電板１３２〜１３４は、絶縁材よりなる絶縁枠１４０内に、相互に絶縁された状態で装着されている。   5 is an enlarged view of the main part on the negative electrode side in FIG. 2, and FIG. 6 is a cross-sectional view taken along the line AA in FIG. As shown in FIGS. 2, 5, and 6, the current collector 130 is divided into a main current collector 131 and three sub current collectors 132 to 134. The main current collecting plate 131 and the three sub current collecting plates 132 to 134 are mounted in an insulated frame 140 made of an insulating material while being insulated from each other.

第１副集電板１３２は、空気側セパレータ１１０の空気流路溝１１３における空気出口部１１２よりも空気入口部１１１に近い位置、詳細には、空気入口部１１１近傍（図３に符号Ｂを付して示す部位）、より詳細には、空気入口部１１１と一部が重なる位置に、対向して配置されている。第１副集電板１３２と主集電板１３１との間は、導電性の第１集電線１５１により接続されている。第１集電線１５１には、この第１集電線１５１を流れる電流を検出する第１電流センサ１６１が装着されている。   The first sub collector plate 132 is closer to the air inlet portion 111 than the air outlet portion 112 in the air flow channel 113 of the air-side separator 110, more specifically, near the air inlet portion 111 (reference symbol B in FIG. 3). (Part shown), more specifically, the air inlet 111 is disposed at a position where it partially overlaps. The first sub collector plate 132 and the main collector plate 131 are connected by a conductive first collector wire 151. A first current sensor 161 that detects a current flowing through the first current collecting line 151 is attached to the first current collecting line 151.

第２副集電板１３３は、水素側セパレータ１２０の水素流路溝１２３における水素出口部１２２よりも水素入口部１２１に近い位置、詳細には、水素入口部１２１近傍（図４に符号Ｃを付して示す部位）、より詳細には、水素入口部１２１と一部が重なる位置に、対向して配置されている。第２副集電板１３３と主集電板１３１との間は、導電性の第２集電線１５２により接続されている。第２集電線１５２には、この第２集電線１５２を流れる電流を検出する第２電流センサ１６２が装着されている。   The second sub collector plate 133 is located closer to the hydrogen inlet 121 than the hydrogen outlet 122 in the hydrogen flow channel 123 of the hydrogen separator 120, more specifically, near the hydrogen inlet 121 (reference symbol C in FIG. 4). (Part shown), more specifically, the hydrogen inlet portion 121 is disposed so as to be opposed to a part of the hydrogen inlet portion 121. The second sub current collector 133 and the main current collector 131 are connected by a conductive second current collector 152. A second current sensor 162 that detects a current flowing through the second power collection line 152 is attached to the second power collection line 152.

第３副集電板１３４は、水素側セパレータ１２０の水素流路溝１２３における水素入口部１２１よりも水素出口部１２２に近い位置、詳細には、水素出口部１２２近傍（図４に符号Ｄを付して示す部位）、より詳細には、水素出口部１２２と一部が重なる位置に、対向して配置されている。第３副集電板１３４と主集電板１３１との間は、導電性の第３集電線１５３により接続されている。第３集電線１５３には、この第３集電線１５３を流れる電流を検出する第３電流センサ１６３が装着されている。   The third sub-current collector plate 134 is closer to the hydrogen outlet portion 122 than the hydrogen inlet portion 121 in the hydrogen flow channel 123 of the hydrogen side separator 120, more specifically, near the hydrogen outlet portion 122 (reference symbol D in FIG. 4). (Part shown), more specifically, the hydrogen outlet portion 122 is disposed so as to face the portion where it partially overlaps. The third sub collector plate 134 and the main collector plate 131 are connected by a conductive third collector wire 153. A third current sensor 163 that detects a current flowing through the third power collection line 153 is attached to the third power collection line 153.

各電流センサ１６１〜１６３は、例えば磁気センサとしてのホール素子を用いることができる。この場合、ギャップを有する鉄心を集電線１５１〜１５３の周囲に配置し、そのギャップ内にホール素子を配置すればよい。集電線１５１〜１５３に電流が流れると、その電流に比例した磁界が集電線１５１〜１５３の周囲に発生する。ホール素子は、電流によって発生した磁界を検出し、電圧に変換する。なお、磁気センサとして、ホール素子の他にＭＲ素子、ＭＩ素子、フラックスゲート等を用いることができる。さらにシャント抵抗を用いた電流センサ等を用いることもできる。   Each of the current sensors 161 to 163 can use, for example, a Hall element as a magnetic sensor. In this case, an iron core having a gap may be disposed around the collector wires 151 to 153, and a Hall element may be disposed in the gap. When a current flows through the current collectors 151 to 153, a magnetic field proportional to the current is generated around the current collectors 151 to 153. The Hall element detects a magnetic field generated by the current and converts it into a voltage. In addition to the Hall element, an MR element, MI element, flux gate, or the like can be used as the magnetic sensor. Furthermore, a current sensor using a shunt resistor can also be used.

また、第１副集電板１３２と第１集電線１５１と第１電流センサ１６１、第２副集電板１３３と第２集電線１５２と第２電流センサ１６２、第３副集電板１３４と第３集電線１５３と第３電流センサ１６３は、それぞれが、本発明の電流測定手段を構成している。   In addition, the first sub current collector 132, the first current collector 151, the first current sensor 161, the second sub current collector 133, the second current collector 152, the second current sensor 162, the third sub current collector 134, Each of the third power collection line 153 and the third current sensor 163 constitutes a current measuring means of the present invention.

上記構成の燃料電池システムの作動を説明する。   The operation of the fuel cell system having the above configuration will be described.

まず、負荷１１からの電力要求に応じて、燃料電池１０への空気供給量および水素供給量を制御する。具体的には、空気ポンプ２１の回転数を制御して空気供給量を制御し、水素ポンプ３４の回転数を制御して水素供給量を制御する。この際、空気供給量は、予め電圧ばらつきを発生しない供給量に設定する。そして、空気および水素の供給により、燃料電池１０では電気化学反応により発電が起こり、発電した電力は負荷１１に供給される。   First, the air supply amount and the hydrogen supply amount to the fuel cell 10 are controlled according to the power demand from the load 11. Specifically, the air supply amount is controlled by controlling the rotational speed of the air pump 21, and the hydrogen supply amount is controlled by controlling the rotational speed of the hydrogen pump 34. At this time, the air supply amount is set in advance to a supply amount that does not cause voltage variation. With the supply of air and hydrogen, the fuel cell 10 generates power by an electrochemical reaction, and the generated power is supplied to the load 11.

負荷１１を通った電流は−極の主集電板１３１に流れ込む。主集電板１３１に流れ込んだ電流は、そのままＭＥＡ１００に流れ込む電流と、第１集電線１５１および第１副集電板１３２を介してＭＥＡ１００に流れ込む電流と、第２集電線１５２および第２副集電板１３３を介してＭＥＡ１００に流れ込む電流と、第３集電線１５３および第３副集電板１３４を介してＭＥＡ１００に流れ込む電流とに分かれる。   The current passing through the load 11 flows into the negative collector plate 131. The current flowing into the main current collecting plate 131 is the current flowing into the MEA 100 as it is, the current flowing into the MEA 100 via the first current collecting wire 151 and the first sub current collecting plate 132, and the second current collecting wire 152 and the second sub current collecting. The current flows into the MEA 100 via the current plate 133 and the current flows into the MEA 100 via the third current collecting wire 153 and the third sub current collecting plate 134.

そして、第１集電線１５１を流れる電流は、ＭＥＡ１００における空気入口部１１１に近い部位を流れる局所電流（以下、空気入口側電流Ｉａ・ｉｎという）に相当するため、第１電流センサ１６１によって、空気入口側電流Ｉａ・ｉｎを検出することができる。   And since the electric current which flows through the 1st current collection line 151 is equivalent to the local electric current (henceforth the air inlet side electric current Ia * in) which flows through the site | part close | similar to the air inlet part 111 in MEA100, it is air current by the 1st current sensor 161. The inlet side current Ia · in can be detected.

また、第２集電線１５２を流れる電流は、ＭＥＡ１００における水素入口部１２１に近い部位を流れる局所電流（以下、水素入口側電流Ｉｈ・ｉｎという）に相当するため、第２電流センサ１６２によって、水素入口側電流Ｉｈ・ｉｎを検出することができる。   In addition, since the current flowing through the second power collecting line 152 corresponds to a local current flowing through a portion near the hydrogen inlet 121 in the MEA 100 (hereinafter referred to as hydrogen inlet side current Ih · in), the second current sensor 162 The inlet side current Ih · in can be detected.

さらに、第３集電線１５３を流れる電流は、ＭＥＡ１００における水素出口部１２２に近い部位を流れる局所電流（以下、水素出口側電流Ｉｈ・ｏｕｔという）に相当するため、第３電流センサ１６３によって、水素出口側電流Ｉｈ・ｏｕｔを検出することができる。   Furthermore, since the current flowing through the third power collection line 153 corresponds to a local current flowing through a portion close to the hydrogen outlet portion 122 in the MEA 100 (hereinafter, referred to as hydrogen outlet side current Ih · out), the third current sensor 163 causes the hydrogen The outlet side current Ih · out can be detected.

ところで、燃料電池１０に供給される空気への加湿量が低下すると、ＭＥＡ１００の電解質膜における、空気入口部１１１に近い部位が乾燥する。図７は、空気湿度ψａの低下に伴って電解質膜の乾燥が発生した際の乾燥発生部における電流Ｉの経時変化を示すもので、電解質膜における乾燥部位ではプロトン伝導抵抗が増加して電流が低下する。   By the way, when the humidification amount to the air supplied to the fuel cell 10 decreases, the portion near the air inlet 111 in the electrolyte membrane of the MEA 100 is dried. FIG. 7 shows the change over time of the current I in the drying generation portion when the electrolyte membrane dries as the air humidity ψa decreases. The proton conduction resistance increases at the drying portion in the electrolyte membrane and the current flows. descend.

同様に、燃料電池１０に供給される水素への加湿量が低下すると、ＭＥＡ１００の電解質膜における水素入口部１２１近傍が乾燥し、乾燥部位ではプロトン伝導抵抗が増加し電流が低下する。なお、水素への加湿量の低下に伴って電解質膜の乾燥が発生した際の乾燥発生部における電流の変化は、図７に示した空気湿度ψａ低下の場合と同様となる。   Similarly, when the amount of humidification to the hydrogen supplied to the fuel cell 10 decreases, the vicinity of the hydrogen inlet 121 in the electrolyte membrane of the MEA 100 is dried, and the proton conduction resistance increases and the current decreases at the dry portion. It should be noted that the change in current in the drying portion when the electrolyte membrane is dried along with the decrease in the amount of humidification to hydrogen is the same as in the case of the decrease in air humidity ψa shown in FIG.

このことから、乾燥が発生しやすい空気入口部１１１近傍や水素入口部１２１近傍の電流Ｉ、すなわち、空気入口側電流Ｉａ・ｉｎや水素入口側電流Ｉｈ・ｉｎを測定することにより、燃料電池１０の電解質膜の乾燥状態を診断することが可能である。具体的には、空気入口側電流Ｉａ・ｉｎや水素入口側電流Ｉｈ・ｉｎが所定電流値未満の場合は、電解質膜の乾燥部位ありと推定することができる。なお、所定電流値は、電解質膜の乾燥がないときの電流値の９０％程度に設定する。   From this, the fuel cell 10 is measured by measuring the current I in the vicinity of the air inlet 111 and the hydrogen inlet 121, that is, the air inlet side current Ia · in and the hydrogen inlet side current Ih · in, which are likely to be dried. It is possible to diagnose the dry state of the electrolyte membrane. Specifically, when the air inlet side current Ia · in and the hydrogen inlet side current Ih · in are less than a predetermined current value, it can be estimated that there is a dry portion of the electrolyte membrane. The predetermined current value is set to about 90% of the current value when the electrolyte membrane is not dried.

逆に、空気や水素への加湿量が過剰になった場合、電極の水分過剰な濡れ状態が発生する。その際には、水素出口部１２２近傍に最も液滴が滞留して水分過剰となりやすく、したがってＭＥＡ１００の電極における水素出口部１２２に近い部位で顕著に発生しやすい。水素出口部１２２近傍に水分過剰となりやすい理由としては、水素入口部１２１から水素流路溝１２３を介して水素出口部１２２に水が輸送されることに加え、水素が消費されるため水素流量が低下しており水の排出力が低下していることが挙げられる。図８は、水素出口部１２２の水滴量Ｖｗの増加に伴って電極が水分過剰状態となった際の、水分過剰部の局所電流Ｉの変化を示すもので、水滴量Ｖｗの増加に伴ってガスの透過が阻害されて電池の出力が低下する。   On the contrary, when the humidification amount to air or hydrogen becomes excessive, the wet state of the electrode with excessive moisture occurs. At that time, the liquid droplets are most likely to stay in the vicinity of the hydrogen outlet portion 122 to cause excess water, and thus are prominently generated at a portion near the hydrogen outlet portion 122 in the electrode of the MEA 100. The reason why water tends to be excessive in the vicinity of the hydrogen outlet portion 122 is that water is transported from the hydrogen inlet portion 121 to the hydrogen outlet portion 122 via the hydrogen passage groove 123, and hydrogen is consumed, so that the hydrogen flow rate is increased. It is reduced and the water discharge capacity is reduced. FIG. 8 shows a change in the local current I in the excess water portion when the electrode is in an excessive water state with an increase in the water drop amount Vw at the hydrogen outlet 122, and as the water drop amount Vw increases. The permeation of gas is hindered and the output of the battery decreases.

また、水素供給量が発電量に対して不足する場合も、水素出口部１２２近傍から水素不足が発生するため、ＭＥＡ１００における水素出口部１２２に近い部位の電流が低下する。図９は、水素供給量Ｑｈが不足した際の、ＭＥＡ１００における水素出口部１２２に近い部位の電流Ｉの変化を示すもので、水素不足が発生すると、直ちに且つ急激に電流Ｉが低下する。   In addition, even when the hydrogen supply amount is insufficient with respect to the power generation amount, a shortage of hydrogen occurs from the vicinity of the hydrogen outlet portion 122, so that the current in a portion near the hydrogen outlet portion 122 in the MEA 100 decreases. FIG. 9 shows a change in the current I at a portion close to the hydrogen outlet 122 in the MEA 100 when the hydrogen supply amount Qh is insufficient. When the hydrogen shortage occurs, the current I immediately and rapidly decreases.

このことから、ＭＥＡ１００における水素出口部１２２に近い部位の電流Ｉ、すなわち水素出口側電流Ｉｈ・ｏｕｔが、所定電流値未満の場合は、水分過剰発生または水素不足発生と推定することができる。なお、所定電流値は、水分過剰状態および水素不足状態の電流値の９０％程度に設定する。   From this, when the current I near the hydrogen outlet portion 122 in the MEA 100, that is, the hydrogen outlet side current Ih · out is less than a predetermined current value, it can be estimated that water is excessively generated or hydrogen is insufficiently generated. The predetermined current value is set to about 90% of the current value in the moisture excess state and the hydrogen deficiency state.

ここで、水分過剰発生時および水素不足発生時は、いずれもＭＥＡ１００における水素出口部１２２に近い部位の電流Ｉが低下するため、電流Ｉの低下要因がいずれであるかを特定する必要がある。   Here, since the current I at the portion near the hydrogen outlet 122 in the MEA 100 decreases when the moisture excess occurs and when the hydrogen shortage occurs, it is necessary to specify which is the cause of the decrease in the current I.

図１０は、水分過剰発生時の、ＭＥＡ１００における水素出口部１２２に近い部位の電流Ｉの変化と、水素不足発生時の、ＭＥＡ１００における水素出口部１２２に近い部位の電流Ｉの変化を示すものである。また、図１１は、水分過剰発生時および水素不足発生時の、ＭＥＡ１００における水素出口部１２２に近い部位の電流Ｉの低下速度（以下、電流低下速度という）を示すものである。なお、本明細書でいう電流低下速度とは、単位時間あたりの電流変化量の絶対値である。図１０、図１１において、実線は水分過剰発生時の特性、破線は水素不足発生時の特性であり、ｔ１は水分過剰や水素不足が発生した時刻である。   FIG. 10 shows changes in the current I near the hydrogen outlet 122 in the MEA 100 when excessive moisture occurs, and changes in the current I near the hydrogen outlet 122 in the MEA 100 when hydrogen shortage occurs. is there. FIG. 11 shows the rate of decrease in current I (hereinafter referred to as the current rate of decrease) at a site close to the hydrogen outlet 122 in the MEA 100 when excess moisture and insufficient hydrogen occur. It should be noted that the current decrease rate in this specification is the absolute value of the current change amount per unit time. In FIGS. 10 and 11, the solid line is the characteristic at the time of excess water generation, the broken line is the characteristic at the time of hydrogen shortage occurrence, and t1 is the time when the water excess or hydrogen shortage occurs.

図１０、図１１に示すように、水分過剰発生時と比較すると、水素不足発生時の電流Ｉは急激に低下する。このことから、電流低下が発生する際の電流低下速度によって電流Ｉの低下要因を特定することが可能である。具体的には、水素出口側電流Ｉｈ・ｏｕｔが所定電流値未満で、且つ電流低下速度が所定低下速度ｄＩ１（図１１参照）未満の場合は水分過剰発生と推定し、水素出口側電流Ｉｈ・ｏｕｔが所定電流値未満で、且つ電流低下速度が所定低下速度ｄＩ１以上の場合は水素不足発生と推定することができる。なお、所定低下速度ｄＩ１は、１．０（ｍＡ／ＳＥＣ／ｃｍ2）程度に設定する。 As shown in FIGS. 10 and 11, the current I when hydrogen shortage occurs is drastically reduced as compared to when water is excessive. From this, it is possible to specify the cause of the decrease in the current I by the current decrease rate when the current decrease occurs. Specifically, when the hydrogen outlet-side current Ih · out is less than a predetermined current value and the current decrease rate is less than the predetermined decrease rate dI1 (see FIG. 11), it is estimated that moisture is excessively generated, and the hydrogen outlet-side current Ih · out When out is less than the predetermined current value and the current decrease rate is equal to or greater than the predetermined decrease rate dI1, it can be estimated that hydrogen shortage has occurred. The predetermined decrease rate dI1 is set to about 1.0 (mA / SEC / cm 2 ).

次に、燃料電池１０の出力低下要因の診断について、図１２に基づいて説明する。図１２は制御部４０（図１参照）にて実行される制御処理のうち、燃料電池１０の出力低下要因の診断にかかわる部分の流れ図である。   Next, the diagnosis of the output reduction factor of the fuel cell 10 will be described based on FIG. FIG. 12 is a flowchart of the portion of the control process executed by the control unit 40 (see FIG. 1) relating to the diagnosis of the output reduction factor of the fuel cell 10.

まず、図示しない電流センサによって燃料電池１０から負荷１１に流れている総電流を測定するとともに（ステップ１０１）、第１電流センサ１６１によって空気入口側電流Ｉａ・ｉｎを測定する（ステップ１０２）。次に、空気入口側電流Ｉａ・ｉｎが第１所定電流値未満である否かを判定する（ステップ１０３）。この「第１所定電流値」は、空気入口部１１１近傍における燃料電池１０の乾燥状態を診断するために予め設定された値である。図１３に示すように、第１所定電流値は燃料電池１０の総電流と関連づけてマップ化されており、ステップ１００で測定した総電流に基づいて求めることができる。   First, the total current flowing from the fuel cell 10 to the load 11 is measured by a current sensor (not shown) (step 101), and the air inlet side current Ia · in is measured by the first current sensor 161 (step 102). Next, it is determined whether or not the air inlet side current Ia · in is less than a first predetermined current value (step 103). This “first predetermined current value” is a value set in advance for diagnosing the dry state of the fuel cell 10 in the vicinity of the air inlet 111. As shown in FIG. 13, the first predetermined current value is mapped in association with the total current of the fuel cell 10 and can be obtained based on the total current measured in step 100.

空気入口側電流Ｉａ・ｉｎが第１所定電流値未満であれば（ステップ１０３がＹＥＳ）、電解質膜の乾燥部位ありと診断する（ステップ１０４）。空気入口側電流Ｉａ・ｉｎが第１所定電流値以上であれば（ステップ１０３がＮＯ）、電解質膜の乾燥部位なしと診断する（ステップ１０５）。因みに、ステップ１０４にて電解質膜の乾燥部位ありと診断された場合には、燃料電池１０に供給される空気の湿度ψａが低いと推測されるため、加湿器２２による空気への加湿量を増加する。   If the air inlet side current Ia · in is less than the first predetermined current value (YES in step 103), it is diagnosed that there is a dry portion of the electrolyte membrane (step 104). If the air inlet side current Ia · in is equal to or greater than the first predetermined current value (NO in step 103), it is diagnosed that there is no dried portion of the electrolyte membrane (step 105). Incidentally, when it is diagnosed in step 104 that there is a dry portion of the electrolyte membrane, it is estimated that the humidity ψa of the air supplied to the fuel cell 10 is low, so the amount of humidification to the air by the humidifier 22 is increased. To do.

次に、第２電流センサ１６２によって水素入口側電流Ｉｈ・ｉｎを測定する（ステップ１０６）。次に、水素入口側電流Ｉｈ・ｉｎが第２所定電流値未満であるか否かを判定する（ステップ１０７）。この「第２所定電流値」は、水素入口部１２１近傍における燃料電池１０の乾燥状態を診断するために予め設定された値である。第２所定電流値は、第１所定電流値と同様、燃料電池１０の総電流と関連づけてマップ化されており、ステップ１００で測定した総電流に基づいて求めることができる。   Next, the hydrogen inlet side current Ih · in is measured by the second current sensor 162 (step 106). Next, it is determined whether or not the hydrogen inlet side current Ih · in is less than a second predetermined current value (step 107). This “second predetermined current value” is a value set in advance for diagnosing the dry state of the fuel cell 10 in the vicinity of the hydrogen inlet 121. Similar to the first predetermined current value, the second predetermined current value is mapped in association with the total current of the fuel cell 10, and can be obtained based on the total current measured in step 100.

水素入口側電流Ｉｈ・ｉｎが第２所定電流値未満であれば（ステップ１０７がＹＥＳ）、電解質膜の乾燥部位ありと診断する（ステップ１０８）。水素入口側電流Ｉｈ・ｉｎが第２所定電流値以上であれば（ステップ１０７がＮＯ）、電解質膜の乾燥部位なしと診断する（ステップ１０９）。因みに、ステップ１０８にて電解質膜の乾燥部位ありと診断された場合には、燃料電池１０に供給される水素への加湿量が少ないと推測されるため、加湿器３３による水素への加湿量を増加する。   If the hydrogen inlet side current Ih · in is less than the second predetermined current value (YES in step 107), it is diagnosed that there is a dry portion of the electrolyte membrane (step 108). If the hydrogen inlet side current Ih · in is equal to or greater than the second predetermined current value (NO in step 107), it is diagnosed that there is no dried portion of the electrolyte membrane (step 109). Incidentally, when it is diagnosed in step 108 that there is a dry portion of the electrolyte membrane, it is estimated that the amount of humidification to hydrogen supplied to the fuel cell 10 is small, so the amount of humidification to hydrogen by the humidifier 33 is reduced. To increase.

次に、第３電流センサ１６３によって水素出口側電流Ｉｈ・ｏｕｔを測定する（ステップ１１０）。次に、水素出口側電流Ｉｈ・ｏｕｔが第３所定電流値未満であるか否かを判定する（ステップ１１１）。この「第３所定電流値」は、水素出口部１２２近傍における燃料電池１０の水分過剰状態を診断するために予め設定された値である。第３所定電流値は、第１所定電流値と同様、燃料電池１０の総電流と関連づけてマップ化されており、ステップ１００で測定した総電流に基づいて求めることができる。   Next, the hydrogen outlet side current Ih · out is measured by the third current sensor 163 (step 110). Next, it is determined whether or not the hydrogen outlet side current Ih · out is less than a third predetermined current value (step 111). This “third predetermined current value” is a value set in advance for diagnosing the excessive water state of the fuel cell 10 in the vicinity of the hydrogen outlet 122. Similarly to the first predetermined current value, the third predetermined current value is mapped in association with the total current of the fuel cell 10 and can be obtained based on the total current measured in step 100.

水素出口側電流Ｉｈ・ｏｕｔが第３所定電流値以上であれば（ステップ１１１がＮＯ）、水分過剰なしまたは水素不足なしと診断する（ステップ１１２）。水素出口側電流Ｉｈ・ｏｕｔが第３所定電流値未満で（ステップ１１１がＹＥＳ）、且つ水素出口側電流Ｉｈ・ｏｕｔの電流低下速度が所定低下速度未満の場合は（ステップ１１３がＹＥＳ）、水分過剰状態であると診断する（ステップ１１４）。因みに、ステップ１１４にて水分過剰状態であると診断された場合には、空気や水素への加湿量が過剰、あるいは、水素流量低下による水の排出力低下と推測されるため、加湿器２２による空気への加湿量および加湿器３３による水素への加湿量をともに減少させるとともに、水素流量を増加させる。   If the hydrogen outlet side current Ih · out is equal to or greater than the third predetermined current value (NO in step 111), it is diagnosed that there is no excess moisture or no shortage of hydrogen (step 112). When the hydrogen outlet side current Ih · out is less than the third predetermined current value (YES in step 111) and the current decreasing rate of the hydrogen outlet side current Ih · out is less than the predetermined decreasing rate (YES in step 113), moisture It is diagnosed that the state is excessive (step 114). Incidentally, if it is diagnosed in step 114 that the moisture is excessive, it is estimated that the amount of humidification to air or hydrogen is excessive, or that the discharge capacity of water is reduced due to a decrease in the hydrogen flow rate. Both the humidification amount to air and the humidification amount to hydrogen by the humidifier 33 are decreased, and the hydrogen flow rate is increased.

また、水素出口側電流Ｉｈ・ｏｕｔが第３所定電流値未満で（ステップ１１１がＹＥＳ）、且つ水素出口側電流Ｉｈ・ｏｕｔの電流低下速度が所定低下速度以上の場合は（ステップ１１３がＮＯ）、水素供給量が不足と診断する（ステップ１１５）。因みに、ステップ１１５にて水素供給量が不足と診断された場合には水素流量を増加させる。   Further, when the hydrogen outlet side current Ih · out is less than the third predetermined current value (YES in step 111) and the current decreasing rate of the hydrogen outlet side current Ih · out is equal to or higher than the predetermined decreasing rate (NO in step 113). Then, it is diagnosed that the hydrogen supply amount is insufficient (step 115). Incidentally, if it is determined in step 115 that the hydrogen supply amount is insufficient, the hydrogen flow rate is increased.

上記した本実施形態によれば、空気入口側電流Ｉａ・ｉｎおよび水素入口側電流Ｉｈ・ｉｎに基づいて電解質膜の乾燥状態を診断し、水素出口側電流Ｉｈ・ｏｕｔと水素出口側電流Ｉｈ・ｏｕｔの電流低下速度とに基づいて水分過剰や水素不足を診断するため、燃料電池１０の出力低下要因を適確に診断することができる。また、燃料電池１０の出力低下要因を特定することができ、したがって出力低下要因に応じた適確な制御を行うことができる。   According to the above-described embodiment, the dry state of the electrolyte membrane is diagnosed based on the air inlet side current Ia · in and the hydrogen inlet side current Ih · in, and the hydrogen outlet side current Ih · out and the hydrogen outlet side current Ih · in Since the excess moisture and the lack of hydrogen are diagnosed based on the current reduction rate of out, the output reduction factor of the fuel cell 10 can be diagnosed accurately. In addition, it is possible to specify the output reduction factor of the fuel cell 10, and therefore it is possible to perform accurate control according to the output reduction factor.

（第２実施形態）
次に、本発明の第２実施形態について説明する。本第２実施形態は、上記第１実施形態に比較して、電流測定手段の構成が異なるものである。 (Second Embodiment)
Next, a second embodiment of the present invention will be described. The second embodiment is different from the first embodiment in the configuration of the current measuring means.

図１４は本第２実施形態の燃料電池システムの構成を示す概念図であり、図１５は本実施形態の燃料電池の斜視図であり、図１６は燃料電池セルの斜視図である。   FIG. 14 is a conceptual diagram showing the configuration of the fuel cell system of the second embodiment, FIG. 15 is a perspective view of the fuel cell of the present embodiment, and FIG. 16 is a perspective view of the fuel cell.

図１６に示すように、本第２実施形態では、第１集電板１４０に集電部材１７１〜１７４が設けられている。集電部材１７１〜１７４は、棒状の導電性部材からなり、第１集電板１４０の板面から突出するように設けられている。主集電板１３１には第１集電部材１７１が設けられ、第１副集電板１３２には第２集電部材１７２が設けられ、第２副集電板１３３には第３集電部材１７３が設けられ、第３副集電板１３４には第４集電部材１７４が設けられている。第２集電板１７０には、第１集電板１４０の各集電部材１７１〜１７４に対応する部位に貫通孔１７０ａ〜１７０ｄが形成されている。   As shown in FIG. 16, in the second embodiment, current collecting members 171 to 174 are provided on the first current collecting plate 140. The current collecting members 171 to 174 are made of a rod-shaped conductive member, and are provided so as to protrude from the plate surface of the first current collecting plate 140. The main current collecting plate 131 is provided with a first current collecting member 171, the first sub current collecting plate 132 is provided with a second current collecting member 172, and the second sub current collecting plate 133 is provided with a third current collecting member. 173 is provided, and a fourth current collecting member 174 is provided on the third sub-current collector plate 134. Through holes 170 a to 170 d are formed in the second current collector plate 170 at portions corresponding to the current collectors 171 to 174 of the first current collector plate 140.

図１４に示すように、燃料電池１０で発電した電流は各集電部材１７１〜１７４を介して電気負荷１１に流れる。図１４、図１５に示すように、各副集電板１３２、１３３、１３４に設けられた集電部材１７２、１７３、１７４を流れる電流値を測定する電流センサ１６４、１６５、１６６が燃料電池１０の外部に設けられている。各電流センサ１６４〜１６６としては、上記第１実施形態と同様、ホール素子その他の電流センサを用いることができる。   As shown in FIG. 14, the current generated by the fuel cell 10 flows to the electric load 11 via the current collecting members 171 to 174. As shown in FIGS. 14 and 15, current sensors 164, 165, 166 that measure current values flowing through current collecting members 172, 173, 174 provided on the sub current collector plates 132, 133, 134 are fuel cell 10. It is provided outside. As each of the current sensors 164 to 166, a Hall element or other current sensor can be used as in the first embodiment.

第１集電部材１７２を流れる電流は、ＭＥＡ１００における空気入口側電流Ｉａ・ｉｎに相当するため、第１の電流センサ１６４によって、空気入口側電流Ｉａ・ｉｎを検出することができる。また、第２の集電部材１７３を流れる電流は、水素入口側電流Ｉｈ・ｉｎに相当するため、第２電流センサ１６５によって、水素入口側電流Ｉｈ・ｉｎを検出することができる。さらに、第３集電部材１７４を流れる電流は、水素出口側電流Ｉｈ・ｏｕｔに相当するため、第３電流センサ１６６によって、水素出口側電流Ｉｈ・ｏｕｔを検出することができる。   Since the current flowing through the first current collecting member 172 corresponds to the air inlet-side current Ia · in in the MEA 100, the first current sensor 164 can detect the air inlet-side current Ia · in. Further, since the current flowing through the second current collecting member 173 corresponds to the hydrogen inlet side current Ih · in, the second current sensor 165 can detect the hydrogen inlet side current Ih · in. Further, since the current flowing through the third current collecting member 174 corresponds to the hydrogen outlet side current Ih · out, the third current sensor 166 can detect the hydrogen outlet side current Ih · out.

また、第１副集電板１３２と第１集電部材１７２と第１電流センサ１６４、第２副集電板１３３と第２集電部材１７３と第２電流センサ１６５、第３副集電板１３４と第３集電部材１７４と第３電流センサ１６６は、それぞれが、本発明の電流測定手段を構成している。   Also, the first sub current collector 132, the first current collector 172, the first current sensor 164, the second sub current collector 133, the second current collector 173, the second current sensor 165, and the third sub current collector. Each of the 134, the third current collecting member 174, and the third current sensor 166 constitutes a current measuring means of the present invention.

上記構成の電流測定手段を用いる構成によっても、上記第１実施形態と同様、燃料電池１０の出力低下要因を適確に診断可能にすることが可能となる。   Also with the configuration using the current measuring means with the above configuration, it is possible to accurately diagnose the output reduction factor of the fuel cell 10 as in the first embodiment.

（第３実施形態）
次に、本発明の第３実施形態について説明する。本第３実施形態は、上記各実施形態に比較して、燃料電池内部が乾燥状態の場合の水分量制御の内容が異なるものである。 (Third embodiment)
Next, a third embodiment of the present invention will be described. The third embodiment is different from the above embodiments in the content of moisture control when the inside of the fuel cell is in a dry state.

図１７は、燃料電池１０の乾燥しやすい部位Ｂである空気入口部１１１近傍において水分状態が変動した場合の発電電流Ｉの変化を示している。図１７に示す例では、燃料電池１０の電流Ｉが所定の基準電流Ｉ1以上となった場合に、燃料電池１０内部が湿潤状態であるとし、燃料電池１０の電流Ｉが基準電流Ｉ1を下回った場合に、燃料電池１０内部が乾燥状態であるとしている。燃料電池１０内部が乾燥状態の場合には、燃料電池１０内部の水分量が少ないほど、燃料電池１０の発電電流Ｉが小さくなる。 FIG. 17 shows a change in the generated current I when the moisture state fluctuates in the vicinity of the air inlet 111, which is a portion B of the fuel cell 10 that is easily dried. In the example shown in FIG. 17, when the current I of the fuel cell 10 becomes equal to or higher than a predetermined reference current I 1 , the inside of the fuel cell 10 is assumed to be in a wet state, and the current I of the fuel cell 10 changes the reference current I 1 . When it falls below, it is supposed that the inside of the fuel cell 10 is in a dry state. When the inside of the fuel cell 10 is in a dry state, the power generation current I of the fuel cell 10 decreases as the amount of water in the fuel cell 10 decreases.

図１８は、燃料電池１０の乾燥しやすい部位Ｂである空気入口部１１１近傍において水分状態が変動した場合の発電電流Ｉと基準電流Ｉ1との差である差分電流ΔＩ（＝Ｉ−Ｉ1）の変化を示している。図１８に示すように、燃料電池１０内部が湿潤状態の場合は差分電流ΔＩがゼロ以上となり、燃料電池１０内部が乾燥状態の場合は差分電流ΔＩがゼロを下回る。また、上述のように、燃料電池１０内部の水分量に応じて燃料電池１０の発電電流Ｉが変化するので、差分電流ΔＩの大きさに基づいて燃料電池１０内部の水分状態の程度を推測することができる。すなわち、差分電流ΔＩがマイナスである場合には、差分電流ΔＩの絶対値が大きいほど燃料電池１０内部の水分不足量が大きくなっており、より乾燥していると判断できる。 FIG. 18 shows a difference current ΔI (= I−I 1) that is a difference between the generated current I and the reference current I 1 when the moisture state fluctuates in the vicinity of the air inlet 111, which is a portion B of the fuel cell 10 that is easily dried. ) Changes. As shown in FIG. 18, the difference current ΔI is zero or more when the fuel cell 10 is in a wet state, and the difference current ΔI is less than zero when the fuel cell 10 is in a dry state. Further, as described above, since the generated current I of the fuel cell 10 changes in accordance with the amount of moisture in the fuel cell 10, the degree of moisture state inside the fuel cell 10 is estimated based on the magnitude of the differential current ΔI. be able to. That is, when the differential current ΔI is negative, it can be determined that the moisture shortage in the fuel cell 10 is larger as the absolute value of the differential current ΔI is larger, and that it is more dry.

次に、本実施形態の燃料電池システムの水分量制御を図１９のフローチャートに基づいて説明する。   Next, the water content control of the fuel cell system of this embodiment will be described based on the flowchart of FIG.

まず、電流センサにより乾燥部位Ｂの局所電流Ｉを測定し（ステップ２００）、基準電流Ｉ1との差である差分電流ΔＩを演算する（ステップ２０１）。次に、差分電流ΔＩがゼロ未満であるか否かを判定する（ステップ２０２）。この結果、差分電流ΔＩがゼロ以上と判定された場合には、燃料電池１０内部が湿潤状態であると推定できるので、加湿器２２による空気への加湿量をゼロにする（ステップ２０３）。一方、差分電流ΔＩがゼロ未満であると判定された場合には、燃料電池１０内部が乾燥状態であると推定できるので、加湿器２２による燃料電池１０への加湿水量をＫ１×｜ΔＩ｜に制御する（ステップ２０４）。Ｋ１は加湿水量を算出するための係数である。 First, the local current I of the dry part B is measured by a current sensor (step 200), and a differential current ΔI that is a difference from the reference current I 1 is calculated (step 201). Next, it is determined whether or not the differential current ΔI is less than zero (step 202). As a result, when it is determined that the difference current ΔI is equal to or greater than zero, it can be estimated that the inside of the fuel cell 10 is in a wet state, so the humidification amount to the air by the humidifier 22 is set to zero (step 203). On the other hand, when it is determined that the difference current ΔI is less than zero, it can be estimated that the inside of the fuel cell 10 is in a dry state, so the amount of humidified water to the fuel cell 10 by the humidifier 22 is K1 × | ΔI |. Control (step 204). K1 is a coefficient for calculating the amount of humidified water.

以上のように、燃料電池１０の局所電流Ｉと基準電流Ｉ1との差である差分電流ΔＩの大きさに基づいて燃料電池１０内部の乾燥状態を推測して加湿水量を制御することで、燃料電池１０内部をより適切な水分状態にすることができる。 As described above, by controlling the amount of humidified water by estimating the dry state inside the fuel cell 10 based on the difference current ΔI that is the difference between the local current I of the fuel cell 10 and the reference current I 1 , The inside of the fuel cell 10 can be brought into a more appropriate moisture state.

（第４実施形態）
次に、本発明の第４実施形態について説明する。本第４実施形態は、上記各実施形態に比較して、燃料電池内部が水分過剰状態の場合の水分量制御の内容が異なるものである。 (Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. The fourth embodiment is different from the above embodiments in the content of the water content control when the fuel cell is in an excessive water state.

図２０は、燃料電池１０の水分過剰となりやすい部位Ｄである水素出口部１２２近傍において水分状態が変動した場合の発電電流Ｉの変化を示している。図２０に示す例では、燃料電池１０の電流Ｉが所定の基準電流Ｉ2以上となった場合に、燃料電池１０内部が水分適正状態であるとし、燃料電池１０の電流Ｉが基準電流Ｉ2を下回った場合に、燃料電池１０内部が水分過剰状態であるとしている。燃料電池１０内部が水分過剰状態である場合には、燃料電池１０内部の水分量が多いほど、燃料電池１０の発電電流Ｉが小さくなる。 FIG. 20 shows a change in the generated current I when the moisture state fluctuates in the vicinity of the hydrogen outlet portion 122, which is the portion D where the moisture in the fuel cell 10 tends to be excessive. In the example shown in FIG. 20, when the current I of the fuel cell 10 is equal to or greater than a predetermined reference current I 2 , the inside of the fuel cell 10 is assumed to be in a proper moisture state, and the current I of the fuel cell 10 is the reference current I 2. It is assumed that the inside of the fuel cell 10 is in an excessive water state. When the inside of the fuel cell 10 is in an excessive water state, the power generation current I of the fuel cell 10 decreases as the amount of water in the fuel cell 10 increases.

図２１は、燃料電池１０の水分過剰となりやすい部位Ｄである水素出口部１２２近傍において水分状態が変動した場合の発電電流Ｉと基準電流Ｉ2との差である差分電流ΔＩ（＝Ｉ−Ｉ2）の変化を示している。図２１に示すように、燃料電池１０内部の水分量が適正状態の場合は差分電流Ｉ2がゼロ以上となり、燃料電池１０内部が水分過剰状態の場合は差分電流ΔＩがゼロを下回る。また、上述のように、燃料電池１０内部の水分量に応じて燃料電池１０の発電電流Ｉが変化するので、差分電流ΔＩの大きさに基づいて燃料電池１０内部の水分状態の程度を推測することができる。すなわち、差分電流ΔＩがマイナスである場合には、差分電流ΔＩの絶対値が大きいほど燃料電池１０内部の水分過剰量がより大きくなっていると判断できる。 FIG. 21 shows a difference current ΔI (= I−I), which is the difference between the generated current I and the reference current I 2 when the moisture state fluctuates in the vicinity of the hydrogen outlet 122, which is a portion D of the fuel cell 10 where the moisture tends to be excessive. 2 ) shows changes. As shown in FIG. 21, the differential current I 2 is zero or more when the water content in the fuel cell 10 is in an appropriate state, and the differential current ΔI is less than zero when the fuel cell 10 is in an excessive water state. Further, as described above, since the generated current I of the fuel cell 10 changes in accordance with the amount of moisture in the fuel cell 10, the degree of moisture state inside the fuel cell 10 is estimated based on the magnitude of the differential current ΔI. be able to. That is, when the difference current ΔI is negative, it can be determined that the excess amount of water in the fuel cell 10 is larger as the absolute value of the difference current ΔI is larger.

次に、本実施形態の燃料電池システムの水分量制御を図２２のフローチャートに基づいて説明する。   Next, the water content control of the fuel cell system of the present embodiment will be described based on the flowchart of FIG.

まず、電流センサにより水分過剰部位Ｄの局所電流Ｉを測定し（ステップ３００）、基準電流Ｉ2との差である差分電流ΔＩを演算する（ステップ３０１）。次に、差分電流ΔＩがゼロ未満であるか否かを判定する（ステップ３０２）。この結果、差分電流ΔＩがゼロ以上と判定された場合には、燃料電池１０内部が水分適正状態であると推定できるので、水素流量の増加率をゼロにする（ステップ３０３）。一方、差分電流ΔＩがゼロ未満であると判定された場合には、燃料電池１０内部が水分過剰状態であると推定できるので、水素流量の増加率をＫ２×｜ΔＩ｜に制御する（ステップ３０４）。Ｋ２は水素流量増加率を算出するための係数である。 First, the current sensor measures the local current I of overhydration site D (step 300), calculates the differential current ΔI is the difference between the reference current I 2 (step 301). Next, it is determined whether or not the differential current ΔI is less than zero (step 302). As a result, when it is determined that the difference current ΔI is zero or more, it can be estimated that the inside of the fuel cell 10 is in a proper moisture state, so the increase rate of the hydrogen flow rate is set to zero (step 303). On the other hand, if it is determined that the differential current ΔI is less than zero, it can be estimated that the fuel cell 10 is in an excessive water state, so the rate of increase in the hydrogen flow rate is controlled to K2 × | ΔI | (step 304). ). K2 is a coefficient for calculating the hydrogen flow rate increase rate.

そして、燃料電池１０への水素供給流量を水素必要流量×（１＋流量増加率）に制御する（ステップ３０５）。水素必要流量は、要求電力を発電するために必要とされる水素流量である。このように水素を過剰に供給することで、水素のガス流で水分過剰部位Ｄにおける水分を押し出すことができる。   Then, the hydrogen supply flow rate to the fuel cell 10 is controlled to the required hydrogen flow rate × (1 + flow rate increase rate) (step 305). The hydrogen required flow rate is a hydrogen flow rate required for generating the required power. By supplying hydrogen excessively in this way, it is possible to push out the water in the excessive water portion D with the hydrogen gas flow.

以上のように、燃料電池１０の局所電流Ｉと基準電流Ｉ2との差である差分電流ΔＩの大きさに基づいて燃料電池１０内部の水分過剰状態を推測して水素供給量を制御することで、燃料電池１０内部をより適切な水分状態にすることができる。 As described above, the hydrogen supply amount is controlled by estimating the excess water state in the fuel cell 10 based on the magnitude of the difference current ΔI that is the difference between the local current I of the fuel cell 10 and the reference current I 2. Thus, the inside of the fuel cell 10 can be brought into a more appropriate moisture state.

（第５実施形態）
次に、本発明の第５実施形態について説明する。本第５実施形態は、上記各実施形態に比較して、燃料電池内部の抵抗値に基づいて燃料電池の水分状態を診断する点が異なるものである。 (Fifth embodiment)
Next, a fifth embodiment of the present invention will be described. The fifth embodiment is different from the above embodiments in that the moisture state of the fuel cell is diagnosed based on the resistance value inside the fuel cell.

図２３は、燃料電池１０の内部抵抗と内部水分量との関係を示している。図２３に示すように、燃料電池１０の内部水分量が増加するとある段階まで内部抵抗は減少し、内部水分量が減少すると内部抵抗が増加するという関係がある。   FIG. 23 shows the relationship between the internal resistance of the fuel cell 10 and the internal moisture content. As shown in FIG. 23, the internal resistance decreases until a certain stage when the internal water content of the fuel cell 10 increases, and the internal resistance increases when the internal water content decreases.

したがって、電流センサ１６１、１６２、１６４、１６５で測定した燃料電池１０の乾燥しやすい部位Ｂ、Ｃの局所電流と、セルモニタ１２で測定した燃料電池１０のセル電圧とに基づいて、燃料電池１０の乾燥しやすい部位における局所内部抵抗Ｒ（＝セル電圧／局所電流）を算出し、この局所内部抵抗Ｒに基づいて燃料電池１０内部の乾燥状態を診断することができる。具体的には、局所内部抵抗Ｒが予め設定した基準内部抵抗Ｒ1より小さい場合には、燃料電池１０内部は乾燥状態であると診断する。燃料電池１０内部が乾燥状態であると診断された場合には、燃料電池１０に供給される水素への加湿量が少ないと推測されるため、加湿器３３による水素への加湿量を増加する。 Therefore, based on the local current of the portions B and C that are easily dried of the fuel cell 10 measured by the current sensors 161, 162, 164, 165, and the cell voltage of the fuel cell 10 measured by the cell monitor 12, A local internal resistance R (= cell voltage / local current) at a portion that is easily dried can be calculated, and the dry state inside the fuel cell 10 can be diagnosed based on the local internal resistance R. Specifically, when the local internal resistance R is the reference internal resistance R 1 smaller than a preset, the fuel cell 10 is diagnosed as being dry. When it is diagnosed that the inside of the fuel cell 10 is in a dry state, it is estimated that the amount of humidification to hydrogen supplied to the fuel cell 10 is small, so the amount of humidification to hydrogen by the humidifier 33 is increased.

同様に、電流センサ１６３、１６６で測定した燃料電池１０の水分過剰になりやすい部位Ｄの局所電流と、セルモニタ１２で測定した燃料電池１０の電圧とに基づいて、燃料電池１０の水分過剰になりやすい部位における局所内部抵抗Ｒを算出し、この局所内部抵抗Ｒに基づいて燃料電池１０内部の水分過剰状態を診断することができる。具体的には、局所抵抗値Ｒが予め設定した基準内部抵抗より大きい場合には、燃料電池１０内部は水分過剰状態であると診断する。水分過剰状態であると診断された場合には、空気や水素への加湿量が過剰、あるいは、水素流量低下による水の排出力低下と推測されるため、加湿器２２による空気への加湿量および加湿器３３による水素への加湿量をともに減少させるとともに、水素流量を増加させる。   Similarly, the fuel cell 10 becomes excessively water based on the local current of the part D that is likely to be excessively watery measured by the current sensors 163 and 166 and the voltage of the fuel cell 10 measured by the cell monitor 12. It is possible to calculate the local internal resistance R at an easy site and diagnose the excess water state inside the fuel cell 10 based on the local internal resistance R. Specifically, when the local resistance value R is larger than the preset reference internal resistance, the fuel cell 10 is diagnosed as being in an excessive water state. When it is diagnosed that the moisture is excessive, it is estimated that the amount of humidification to air or hydrogen is excessive, or that the discharge capacity of water is reduced due to a decrease in the hydrogen flow rate. Both the amount of humidification to hydrogen by the humidifier 33 is decreased and the hydrogen flow rate is increased.

以上の構成によっても、燃料電池１０の出力低下要因を適確に診断することができる。また、燃料電池１０の出力低下要因を特定することができ、したがって出力低下要因に応じた適確な制御を行うことができる。   Even with the above configuration, the output reduction factor of the fuel cell 10 can be accurately diagnosed. In addition, it is possible to specify the output reduction factor of the fuel cell 10, and therefore it is possible to perform accurate control according to the output reduction factor.

（第６実施形態）
次に、本発明の第６実施形態について説明する。本第６実施形態は、上記各実施形態に比較して、燃料電池内部の抵抗値に基づいて燃料電池の乾燥状態の程度を診断し、水分量制御をする点が異なるものである。 (Sixth embodiment)
Next, a sixth embodiment of the present invention will be described. The sixth embodiment is different from the above embodiments in that the degree of dryness of the fuel cell is diagnosed based on the resistance value inside the fuel cell and the amount of water is controlled.

図２４は、燃料電池１０の乾燥しやすい部位Ｂである空気入口部１１１近傍において水分状態が変動した場合の局所抵抗値Ｒの変化を示している。図２４に示す例では、燃料電池１０の局所内部抵抗Ｒが所定の基準内部抵抗Ｒ1を上回った場合に、燃料電池１０内部が乾燥状態であるとし、燃料電池１０の局所内部抵抗Ｒが基準内部抵抗Ｒ1以下となった場合に、燃料電池１０内部が湿潤状態であるとしている。燃料電池１０内部が乾燥状態の場合には、燃料電池１０内部の水分量が少ないほど、燃料電池１０の局所内部抵抗Ｒが大きくなる。 FIG. 24 shows a change in the local resistance value R when the moisture state fluctuates in the vicinity of the air inlet 111, which is a portion B of the fuel cell 10 that is easily dried. In the example shown in FIG. 24, when the local internal resistance R of the fuel cell 10 exceeds the predetermined reference internal resistance R 1, the fuel cell 10 is to be dry, the reference local internal resistance R of the fuel cell 10 when it becomes an internal resistance R 1 or less, the fuel cell 10 is to be wet. When the inside of the fuel cell 10 is in a dry state, the local internal resistance R of the fuel cell 10 increases as the amount of water in the fuel cell 10 decreases.

図２５は、燃料電池１０の乾燥しやすい部位Ｂである空気入口部１１１近傍において水分状態が変動した場合の局所内部抵抗Ｒと基準内部抵抗Ｒ1との差である差分抵抗ΔＲ（＝Ｒ−Ｒ1）の変化を示している。図１８に示すように、燃料電池１０内部が湿潤状態の場合は差分抵抗ΔＲがゼロ以下となり、燃料電池１０内部が乾燥状態の場合は差分抵抗ΔＲがゼロを上回る。また、上述のように、燃料電池１０内部の水分量に応じて燃料電池１０の局所内部抵抗Ｒが変化するので、差分抵抗ΔＲの大きさに基づいて燃料電池１０内部の水分状態の程度を推測することができる。すなわち、差分抵抗ΔＲがプラスである場合には、差分抵抗ΔＲの絶対値が大きいほど燃料電池１０内部の水分不足量が大きくなっており、より乾燥していると判断できる。 FIG. 25 shows a differential resistance ΔR (= R−) which is the difference between the local internal resistance R and the reference internal resistance R 1 when the moisture state fluctuates in the vicinity of the air inlet 111, which is the portion B of the fuel cell 10 that is easy to dry. The change in R 1 ) is shown. As shown in FIG. 18, when the inside of the fuel cell 10 is in a wet state, the differential resistance ΔR is not more than zero, and when the inside of the fuel cell 10 is in a dry state, the differential resistance ΔR exceeds zero. Further, as described above, since the local internal resistance R of the fuel cell 10 changes according to the amount of water inside the fuel cell 10, the degree of the moisture state inside the fuel cell 10 is estimated based on the magnitude of the differential resistance ΔR. can do. That is, when the differential resistance ΔR is positive, it can be determined that the moisture shortage in the fuel cell 10 is larger as the absolute value of the differential resistance ΔR is larger, and that the dryness is more dry.

次に、本実施形態の燃料電池システムの水分量制御を図２６のフローチャートに基づいて説明する。   Next, the water content control of the fuel cell system of the present embodiment will be described based on the flowchart of FIG.

まず、電流センサにより乾燥部位Ｂの局所電流を測定し（ステップ４００）、セルモニタ１２によりセル電圧を測定し（ステップ４０１）、セル電圧を局所電流で除して局所内部抵抗Ｒを算出する（ステップ４０２）。次に、局所抵抗Ｒと基準内部抵抗Ｒ1との差である差分抵抗ΔＲを演算する（ステップ４０３）。 First, the local current of the dry region B is measured by the current sensor (step 400), the cell voltage is measured by the cell monitor 12 (step 401), and the local internal resistance R is calculated by dividing the cell voltage by the local current (step 401). 402). Next, a differential resistance ΔR that is a difference between the local resistance R and the reference internal resistance R 1 is calculated (step 403).

次に、差分抵抗ΔＲがゼロを上回っているか否かを判定する（ステップ４０４）。この結果、差分抵抗ΔＲがゼロ以下と判定された場合には、燃料電池１０内部が湿潤状態であると推定できるので、加湿器２２による空気への加湿量をゼロにする（ステップ４０５）。一方、差分電流ΔＩがゼロを上回っていると判定された場合には、燃料電池１０内部が乾燥状態であると推定できるので、加湿器２２による燃料電池１０への加湿水量をＫ３×｜ΔＲ｜に制御する（ステップ４０６）。Ｋ３は加湿水量を算出するための係数である。   Next, it is determined whether or not the differential resistance ΔR exceeds zero (step 404). As a result, when it is determined that the differential resistance ΔR is equal to or less than zero, it can be estimated that the inside of the fuel cell 10 is in a wet state, so the humidification amount to the air by the humidifier 22 is set to zero (step 405). On the other hand, if it is determined that the differential current ΔI is greater than zero, it can be estimated that the inside of the fuel cell 10 is in a dry state, so the amount of humidified water to the fuel cell 10 by the humidifier 22 is expressed as K3 × | ΔR | (Step 406). K3 is a coefficient for calculating the amount of humidified water.

以上のように、燃料電池１０の局所抵抗Ｉと基準内部抵抗Ｒ1との差である差分抵抗ΔＲの大きさに基づいて燃料電池１０内部の乾燥状態を推測して加湿水量を制御することで、燃料電池１０内部をより適切な水分状態にすることができる。 As described above, the amount of humidified water is controlled by estimating the dry state inside the fuel cell 10 based on the difference resistance ΔR, which is the difference between the local resistance I of the fuel cell 10 and the reference internal resistance R 1. The interior of the fuel cell 10 can be brought into a more appropriate moisture state.

（第７実施形態）
次に、本発明の第７実施形態について説明する。本第７実施形態は、上記各実施形態に比較して、燃料電池内部の抵抗値に基づいて燃料電池の水分過剰状態の程度を診断し、水分量制御をする点が異なるものである。 (Seventh embodiment)
Next, a seventh embodiment of the present invention will be described. The seventh embodiment is different from the above-described embodiments in that the degree of moisture excess state of the fuel cell is diagnosed based on the resistance value inside the fuel cell, and the moisture amount is controlled.

図２７は、燃料電池１０の水分過剰となりやすい部位Ｄである水素出口部１２２近傍において水分状態が変動した場合の局所内部抵抗Ｒの変化を示している。図２７に示す例では、燃料電池１０の局所内部抵抗Ｒが所定の基準内部抵抗Ｒ2以下となった場合に、燃料電池１０内部が水分適正状態であるとし、燃料電池１０の局所内部抵抗Ｒが所定の基準内部抵抗Ｒ2を上回った場合に、燃料電池１０内部が水分過剰状態であるとしている。燃料電池１０内部が水分過剰状態である場合には、燃料電池１０内部の水分量が多いほど、燃料電池１０の局所内部抵抗Ｒが大きくなる。 FIG. 27 shows a change in local internal resistance R when the moisture state fluctuates in the vicinity of the hydrogen outlet portion 122, which is a portion D that tends to be excessive in the fuel cell 10. In the example shown in FIG. 27, when the local internal resistance R of the fuel cell 10 is equal to or less than a predetermined reference internal resistance R 2 , it is assumed that the inside of the fuel cell 10 is in a proper moisture state, and the local internal resistance R of the fuel cell 10 is When the value exceeds a predetermined reference internal resistance R 2 , the inside of the fuel cell 10 is assumed to be in an excessive water state. When the inside of the fuel cell 10 is in an excessive water state, the local internal resistance R of the fuel cell 10 increases as the amount of water in the fuel cell 10 increases.

図２８は、燃料電池１０の水分過剰となりやすい部位Ｄである水素出口部１２２近傍において水分状態が変動した場合の局所内部抵抗Ｒと基準内部抵抗Ｒ2との差である差分抵抗ΔＲ（＝Ｒ−Ｒ2）の変化を示している。図２８に示すように、燃料電池１０内部の水分量が適正状態の場合は差分抵抗Ｒ2がゼロ以下となり、燃料電池１０内部が水分過剰状態の場合は差分抵抗Ｒ2がゼロを上回る。また、上述のように、燃料電池１０内部の水分量に応じて燃料電池１０の局所内部抵抗Ｒが変化するので、差分抵抗ΔＲの大きさに基づいて燃料電池１０内部の水分状態の程度を推測することができる。すなわち、差分抵抗ΔＲがプラスである場合には、差分抵抗ΔＲの絶対値が大きいほど燃料電池１０内部の水分過剰量がより大きくなっていると判断できる。 FIG. 28 shows a differential resistance ΔR (= R), which is the difference between the local internal resistance R and the reference internal resistance R 2 when the water state fluctuates in the vicinity of the hydrogen outlet portion 122, which is the portion D that tends to be excessive in the fuel cell 10. -R 2 ) change. As shown in FIG. 28, when the water content in the fuel cell 10 is in an appropriate state, the differential resistance R 2 becomes zero or less, and when the fuel cell 10 has an excessive water content, the differential resistance R 2 exceeds zero. Further, as described above, since the local internal resistance R of the fuel cell 10 changes according to the amount of water inside the fuel cell 10, the degree of the moisture state inside the fuel cell 10 is estimated based on the magnitude of the differential resistance ΔR. can do. That is, when the differential resistance ΔR is positive, it can be determined that the excess amount of water in the fuel cell 10 is larger as the absolute value of the differential resistance ΔR is larger.

次に、本実施形態の燃料電池システムの水分量制御を図２９のフローチャートに基づいて説明する。   Next, the water content control of the fuel cell system of this embodiment will be described based on the flowchart of FIG.

まず、電流センサにより水分過剰部位Ｄの局所電流Ｉを測定し（ステップ５００）、セルモニタ１２によりセル電圧を測定し（ステップ５０１）、セル電圧を局所電流で除して局所内部抵抗Ｒを算出する（ステップ５０２）。次に、局所抵抗Ｒと基準内部抵抗Ｒ2との差である差分抵抗ΔＲを演算する（ステップ５０３）。 First, the local current I of the excessive water portion D is measured by the current sensor (step 500), the cell voltage is measured by the cell monitor 12 (step 501), and the local internal resistance R is calculated by dividing the cell voltage by the local current. (Step 502). Next, a differential resistance ΔR that is a difference between the local resistance R and the reference internal resistance R 2 is calculated (step 503).

次に、差分抵抗ΔＲがゼロを上回っている否かを判定する（ステップ５０４）。この結果、差分抵抗ΔＲがゼロ以下と判定された場合には、燃料電池１０内部が水分適正状態であると推定できるので、水素流量の増加率をゼロにする（ステップ５０５）。一方、差分抵抗ΔＲがゼロを上回っている判定された場合には、燃料電池１０内部が水分過剰状態であると推定できるので、水素流量の増加率をＫ４×｜ΔＩ｜に制御する（ステップ５０６）。Ｋ４は水素流量増加率を算出するための係数である。   Next, it is determined whether or not the differential resistance ΔR exceeds zero (step 504). As a result, if it is determined that the differential resistance ΔR is equal to or less than zero, it can be estimated that the inside of the fuel cell 10 is in a proper moisture state, and therefore the rate of increase in the hydrogen flow rate is set to zero (step 505). On the other hand, if it is determined that the differential resistance ΔR is greater than zero, it can be estimated that the fuel cell 10 is in an excessive water state, so the rate of increase in the hydrogen flow rate is controlled to K4 × | ΔI | (step 506). ). K4 is a coefficient for calculating the hydrogen flow rate increase rate.

そして、燃料電池１０への水素供給流量を水素必要流量×（１＋流量増加率）に制御する（ステップ５０７）。水素必要流量は、要求電力を発電するために必要とされる水素流量である。このように水素を過剰に供給することで、水素のガス流で水分過剰部位Ｄにおける水分を押し出すことができる。   Then, the hydrogen supply flow rate to the fuel cell 10 is controlled to the hydrogen required flow rate × (1 + flow rate increase rate) (step 507). The hydrogen required flow rate is a hydrogen flow rate required for generating the required power. By supplying hydrogen excessively in this way, it is possible to push out the water in the excessive water portion D with the hydrogen gas flow.

以上のように、燃料電池１０の局所内部抵抗Ｒと基準内部抵抗Ｒ2との差である差分抵抗ΔＲの大きさに基づいて燃料電池１０内部の水分過剰状態を推測して水素供給量を制御することで、燃料電池１０内部をより適切な水分状態にすることができる。 As described above, the hydrogen supply amount is controlled by estimating the excess water state in the fuel cell 10 based on the magnitude of the differential resistance ΔR, which is the difference between the local internal resistance R of the fuel cell 10 and the reference internal resistance R 2. By doing so, the inside of the fuel cell 10 can be brought into a more appropriate moisture state.

（他の実施形態）
なお、上記各実施形態では、燃料電池として固体高分子型電解質膜を備えるものを用いたが、これに限らず、本発明は例えば無機材料系の電解質を備える燃料電池にも適用可能である。 (Other embodiments)
In each of the above embodiments, the fuel cell including the solid polymer electrolyte membrane is used. However, the present invention is not limited to this, and the present invention can be applied to, for example, a fuel cell including an inorganic material electrolyte.

本発明の第１実施形態に係る燃料電池システムの全体構成を示す模式図である。It is a mimetic diagram showing the whole fuel cell system composition concerning a 1st embodiment of the present invention. 図１の燃料電池１０の単セルを示す模式的な斜視図である。It is a typical perspective view which shows the single cell of the fuel cell 10 of FIG. 図２の右側から見た空気側セパレータ１１０の透視図である。FIG. 3 is a perspective view of an air side separator 110 viewed from the right side of FIG. 2. 図２の右側から見た水素側セパレータ１２０の透視図である。FIG. 3 is a perspective view of a hydrogen separator 120 viewed from the right side of FIG. 2. 図２における−極側の要部の拡大図である。FIG. 3 is an enlarged view of a main part on the negative side in FIG. 2. 図５のＡ−Ａ線に沿う断面図である。It is sectional drawing which follows the AA line of FIG. 電解質膜の乾燥が発生した際の電流Ｉの変化を示す特性図である。It is a characteristic view which shows the change of the electric current I when drying of an electrolyte membrane generate | occur | produced. 水素出口部の水滴量増加による水分過剰が発生した際の電流Ｉの変化を示す特性図である。It is a characteristic view which shows the change of the electric current I when the water | moisture-content excess generate | occur | produces by the amount of water drops of a hydrogen exit part. 水素供給量が不足した際の電流Ｉの変化を示す特性図である。It is a characteristic view which shows the change of the electric current I when hydrogen supply amount is insufficient. 水分過剰発生時および水素不足発生時の電流Ｉの変化を示す特性図である。It is a characteristic view which shows the change of the electric current I at the time of water | moisture-content excess generation | occurrence | production and hydrogen shortage generation | occurrence | production. 水分過剰発生時および水素不足発生時の電流Ｉの低下速度を示す特性図である。It is a characteristic figure which shows the fall rate of the electric current I at the time of water | moisture-content excess generation | occurrence | production and hydrogen shortage generation | occurrence | production. 図１の制御部４０にて実行される制御処理を示す流れ図である。It is a flowchart which shows the control processing performed in the control part 40 of FIG. 乾燥判定時における総電流値と所定電流値との関係を示す特性図である。It is a characteristic view which shows the relationship between the total electric current value at the time of drying determination, and a predetermined electric current value. 本発明の第２実施形態に係る燃料電池システムの全体構成を示す模式図である。It is a schematic diagram which shows the whole structure of the fuel cell system which concerns on 2nd Embodiment of this invention. 図１４の燃料電池１０を示す模式的な斜視図である。It is a typical perspective view which shows the fuel cell 10 of FIG. 図１４の燃料電池１０の単セルを示す模式的な斜視図である。It is a typical perspective view which shows the single cell of the fuel cell 10 of FIG. 第３実施形態の水分状態が変動した場合の燃料電池の発電電流Ｉの変化を示す特性図である。It is a characteristic view which shows the change of the electric power generation electric current I of a fuel cell when the moisture state of 3rd Embodiment fluctuates. 水分状態が変動した場合の差分電圧ΔＩの変化を示す特性図である。It is a characteristic view which shows the change of the difference voltage (DELTA) I when a moisture state fluctuates. 第３実施形態の水分量制御の内容を示すフローチャートである。It is a flowchart which shows the content of the moisture content control of 3rd Embodiment. 第４実施形態の水分状態が変動した場合の燃料電池の発電電流Ｉの変化を示す特性図である。It is a characteristic view which shows the change of the electric power generation electric current I of the fuel cell when the moisture condition of 4th Embodiment fluctuates. 水分状態が変動した場合の差分電圧ΔＩの変化を示す特性図である。It is a characteristic view which shows the change of the difference voltage (DELTA) I when a moisture state fluctuates. 第４実施形態の水分量制御の内容を示すフローチャートである。It is a flowchart which shows the content of the moisture content control of 4th Embodiment. 第５実施形態の燃料電池の局所内部抵抗と内部水分量との関係を示す特性図である。It is a characteristic view which shows the relationship between the local internal resistance of the fuel cell of 5th Embodiment, and internal moisture content. 第６実施形態の水分状態が変動した場合の燃料電池の局所内部抵抗Ｉの変化を示す特性図である。It is a characteristic view which shows the change of the local internal resistance I of a fuel cell when the moisture state of 6th Embodiment fluctuates. 水分状態が変動した場合の差分抵抗ΔＩの変化を示す特性図である。It is a characteristic view which shows the change of differential resistance (DELTA) I when a moisture state fluctuates. 第６実施形態の水分量制御の内容を示すフローチャートである。It is a flowchart which shows the content of the moisture content control of 6th Embodiment. 第７実施形態の水分状態が変動した場合の燃料電池の局所内部抵抗Ｉの変化を示す特性図である。It is a characteristic figure showing change of local internal resistance I of a fuel cell when the moisture state of a 7th embodiment changes. 水分状態が変動した場合の差分抵抗ΔＩの変化を示す特性図である。It is a characteristic view which shows the change of differential resistance (DELTA) I when a moisture state fluctuates. 第７実施形態の水分量制御の内容を示すフローチャートである。It is a flowchart which shows the content of the moisture content control of 7th Embodiment.

符号の説明Explanation of symbols

１０…燃料電池、１２…セルモニタ、４０…制御部（診断手段）、１６１〜１６６…電流測定手段の主要部をなす電流センサ。   DESCRIPTION OF SYMBOLS 10 ... Fuel cell, 12 ... Cell monitor, 40 ... Control part (diagnosis means), 161-166 ... Current sensor which makes the principal part of an electric current measurement means.

Claims (15)

酸化剤ガスと燃料ガスとの電気化学反応により電気エネルギを発生させる燃料電池（１０）と、
前記燃料電池（１０）内において乾燥しやすい部位（Ｂ、Ｃ）を流れる電流を測定する電流測定手段（１３２、１３３、１５１、１５２、１６１、１６２、１６４、１６５、１７２、１７３）と、
前記電流測定手段で測定された電流値に基づいて前記燃料電池（１０）内部の乾燥状態を診断する診断手段（４０）とを備えることを特徴とする燃料電池システム。 A fuel cell (10) for generating electrical energy by an electrochemical reaction between an oxidant gas and a fuel gas;
Current measuring means (132, 133, 151, 152, 161, 162, 164, 165, 172, 173) for measuring a current flowing through a portion (B, C) that is easily dried in the fuel cell (10);
A fuel cell system comprising: a diagnosis unit (40) for diagnosing a dry state inside the fuel cell (10) based on a current value measured by the current measurement unit. 前記診断手段は、前記電流測定手段にて測定した電流が所定電流値未満のときは、前記燃料電池が乾燥状態であると診断することを特徴とする請求項１に記載の燃料電池システム。 2. The fuel cell system according to claim 1, wherein the diagnosis unit diagnoses that the fuel cell is in a dry state when the current measured by the current measurement unit is less than a predetermined current value. 前記電流測定手段で測定された電流値と、予め設定された所定電流値との差に基づいて前記燃料電池（１０）内部の乾燥状態の程度を診断することを特徴とする請求項１に記載の燃料電池システム。 The degree of dryness inside the fuel cell (10) is diagnosed based on a difference between a current value measured by the current measuring means and a predetermined current value set in advance. Fuel cell system. 前記燃料電池の電圧を測定する電圧測定手段（１２）を備え、
前記診断手段は、前記電圧測定手段で測定された電圧値と前記電流測定手段で測定された電流値とに基づいて、前記燃料電池（１０）内において乾燥しやすい部位の抵抗値を演算し、前記抵抗値に基づいて前記燃料電池内部の乾燥状態を診断することを特徴とする請求項１に記載の燃料電池システム。 Voltage measuring means (12) for measuring the voltage of the fuel cell;
The diagnostic means calculates a resistance value of a portion that is easily dried in the fuel cell (10) based on the voltage value measured by the voltage measuring means and the current value measured by the current measuring means, The fuel cell system according to claim 1, wherein a dry state inside the fuel cell is diagnosed based on the resistance value. 前記燃料電池（１０）は、電解質膜の両側に一対の電極が配置された電解質・電極接合体（１００）と、前記電解質・電極接合体の外側に配置されるとともに前記酸化剤ガスの流路となる酸化剤ガス流路（１１３）が形成された第１セパレータ（１１０）と、前記電解質・電極接合体の外側に配置されるとともに前記燃料ガスの流路となる燃料ガス流路（１２３）が形成された第２セパレータ（１２０）とを備え、
前記電流測定手段（１３２、１５１、１６１、１６４、１７２）は、前記酸化剤ガス流路における酸化剤ガスの出口部（１１２）よりも酸化剤ガスの入口部（１１１）に近い位置で電流を測定することを特徴とする請求項１ないし４のいずれか１つに記載の燃料電池システム。 The fuel cell (10) includes an electrolyte / electrode assembly (100) in which a pair of electrodes are arranged on both sides of an electrolyte membrane, and an outside of the electrolyte / electrode assembly and a flow path for the oxidant gas. A first separator (110) in which an oxidant gas flow path (113) is formed, and a fuel gas flow path (123) that is disposed outside the electrolyte-electrode assembly and serves as a flow path for the fuel gas A second separator (120) formed with
The current measuring means (132, 151, 161, 164, 172) supplies current at a position closer to the oxidant gas inlet (111) than the oxidant gas outlet (112) in the oxidant gas flow path. The fuel cell system according to any one of claims 1 to 4, wherein the fuel cell system is measured. 前記燃料電池（１０）は、電解質膜の両側に一対の電極が配置された電解質・電極接合体（１００）と、前記電解質・電極接合体の外側に配置されるとともに前記酸化剤ガスの流路となる酸化剤ガス流路（１１３）が形成された第１セパレータ（１１０）と、前記電解質・電極接合体の外側に配置されるとともに前記燃料ガスの流路となる燃料ガス流路（１２３）が形成された第２セパレータ（１２０）とを備え、
前記電流測定手段（１３３、１５２、１６２、１６５、１７３）は、前記燃料ガス流路における燃料ガスの出口部（１２２）よりも燃料ガスの入口部（１２１）に近い位置で電流を測定することを特徴とする請求項１ないし４のいずれか１つに記載の燃料電池システム。 The fuel cell (10) includes an electrolyte / electrode assembly (100) in which a pair of electrodes are arranged on both sides of an electrolyte membrane, and an outside of the electrolyte / electrode assembly and a flow path for the oxidant gas. A first separator (110) in which an oxidant gas flow path (113) is formed, and a fuel gas flow path (123) that is disposed outside the electrolyte-electrode assembly and serves as a flow path for the fuel gas A second separator (120) formed with
The current measuring means (133, 152, 162, 165, 173) measures current at a position closer to the fuel gas inlet (121) than the fuel gas outlet (122) in the fuel gas flow path. The fuel cell system according to any one of claims 1 to 4, wherein: 酸化剤ガスと燃料ガスとの電気化学反応により電気エネルギを発生させる燃料電池（１０）と、
前記燃料電池（１０）内において水分が過剰となりやすい部位（Ｄ）を流れる電流を測定する電流測定手段（１３４、１５３、１６３、１６６、１７４）と、
前記電流測定手段にて測定した電流値に基づいて前記燃料電池の水分過剰状態を診断する診断手段（４０）を備えることを特徴とする燃料電池システム。 A fuel cell (10) for generating electrical energy by an electrochemical reaction between an oxidant gas and a fuel gas;
Current measuring means (134, 153, 163, 166, 174) for measuring a current flowing through a portion (D) where moisture tends to be excessive in the fuel cell (10);
A fuel cell system comprising diagnostic means (40) for diagnosing an excessive water state of the fuel cell based on a current value measured by the current measuring means. 前記診断手段は、前記電流測定手段にて測定した電流が所定電流値未満のときは、前記燃料電池が水分過剰状態であると診断することを特徴とする請求項７に記載の燃料電池システム。 8. The fuel cell system according to claim 7, wherein the diagnosis unit diagnoses that the fuel cell is in an excessive water state when the current measured by the current measurement unit is less than a predetermined current value. 前記電流測定手段で測定された電流値と、予め設定された所定電流値との差に基づいて前記燃料電池（１０）内部の水分過剰状態の程度を診断することを特徴とする請求項７に記載の燃料電池システム。 8. The degree of moisture excess inside the fuel cell (10) is diagnosed based on a difference between a current value measured by the current measuring means and a predetermined current value set in advance. The fuel cell system described. 前記燃料電池の電圧を測定する電圧測定手段（１２）を備え、
前記診断手段は、前記電圧測定手段で測定された電圧値と前記電流測定手段で測定された電流値とに基づいて、前記燃料電池（１０）内において水分過剰となりやすい部位の抵抗値を演算し、前記抵抗値に基づいて前記燃料電池内部の水分過剰状態を診断することを特徴とする請求項７に記載の燃料電池システム。 Voltage measuring means (12) for measuring the voltage of the fuel cell;
The diagnostic means calculates a resistance value of a portion that tends to be excessive in the fuel cell (10) based on the voltage value measured by the voltage measuring means and the current value measured by the current measuring means. The fuel cell system according to claim 7, wherein an excess water state inside the fuel cell is diagnosed based on the resistance value. 酸化剤ガスと燃料ガスとの電気化学反応により電気エネルギを発生させる燃料電池（１０）と、
前記燃料電池（１０）内において燃料ガスが不足しやすい部位（Ｄ）を流れる電流を測定する電流測定手段（１３４、１５３、１６３、１６６、１７４）と、
前記電流測定手段にて測定した電流値に基づいて前記燃料電池の燃料ガスの不足状態を診断する診断手段（４０）を備えることを特徴とする燃料電池システム。 A fuel cell (10) for generating electrical energy by an electrochemical reaction between an oxidant gas and a fuel gas;
Current measuring means (134, 153, 163, 166, 174) for measuring a current flowing through a portion (D) where the fuel gas is likely to be insufficient in the fuel cell (10);
A fuel cell system comprising diagnostic means (40) for diagnosing a shortage of fuel gas in the fuel cell based on a current value measured by the current measuring means. 前記診断手段（４０）は、前記電流測定手段にて測定した電流が所定電流値未満で、且つ前記電流測定手段にて測定した電流の低下速度が所定低下速度以上であるときは、前記燃料電池への燃料ガスの供給量が不足していると診断することを特徴とする請求項１１に記載の燃料電池システム。 When the current measured by the current measuring unit is less than a predetermined current value and the rate of current decrease measured by the current measuring unit is equal to or higher than a predetermined rate, the diagnostic unit (40) The fuel cell system according to claim 11, wherein the fuel cell system is diagnosed as having an insufficient fuel gas supply amount. 酸化剤ガスと燃料ガスとの電気化学反応により電気エネルギを発生させる燃料電池（１０）と、
前記燃料電池（１０）内において水分過剰になりやすく且つ燃料ガスが不足しやすい部位（Ｄ）を流れる電流を測定する電流測定手段（１３４、１５３、１６３）と、
前記電流測定手段で測定した電流の低下速度に基づいて、前記燃料電池の水分過剰と前記燃料電池の燃料ガス不足とを区別して診断する診断手段（４０）とを備えることを特徴とする燃料電池システム。 A fuel cell (10) for generating electrical energy by an electrochemical reaction between an oxidant gas and a fuel gas;
Current measuring means (134, 153, 163) for measuring a current flowing through a portion (D) in the fuel cell (10) that is likely to be excessive in water and short of fuel gas;
A fuel cell comprising diagnostic means (40) for distinguishing and diagnosing excess water in the fuel cell and insufficient fuel gas in the fuel cell based on a current decrease rate measured by the current measuring means. system. 前記診断手段は、前記電流測定手段にて測定した電流が所定電流値未満で、且つ前記電流測定手段にて測定した電流の低下速度が所定低下速度未満であるときは、前記燃料電池の水分が過剰になっていると診断し、前記電流測定手段にて測定した電流が前記所定電流値未満で、且つ前記電流測定手段にて測定した電流の低下速度が前記所定低下速度以上であるときは、前記燃料電池への燃料ガスの供給量が不足していると診断することを特徴とする請求項１３に記載の燃料電池システム。 When the current measured by the current measuring unit is less than a predetermined current value and the rate of decrease in current measured by the current measuring unit is less than a predetermined rate of decrease, When the current measured by the current measuring unit is less than the predetermined current value and the current decreasing rate measured by the current measuring unit is equal to or higher than the predetermined decreasing rate, The fuel cell system according to claim 13, wherein a diagnosis is made that a supply amount of fuel gas to the fuel cell is insufficient. 前記燃料電池（１０）は、電解質膜の両側に一対の電極が配置された電解質・電極接合体（１００）と、前記電解質・電極接合体の外側に配置されるとともに前記酸化剤ガスの流路となる酸化剤ガス流路（１１３）が形成された第１セパレータ（１１０）と、前記電解質・電極接合体の外側に配置されるとともに前記燃料ガスの流路となる燃料ガス流路（１２３）が形成された第２セパレータ（１２０）とを備え、
前記電流測定手段（１３４、１５３、１６３、１６６、１７４）は、前記燃料ガス流路における燃料ガスの入口部（１２１）よりも燃料ガスの出口部（１２２）に近い位置で電流を測定することを特徴とする請求項７ないし１４のいずれか１つに記載の燃料電池システム。
The fuel cell (10) includes an electrolyte / electrode assembly (100) in which a pair of electrodes are arranged on both sides of an electrolyte membrane, and an outside of the electrolyte / electrode assembly and a flow path for the oxidant gas. A first separator (110) in which an oxidant gas flow path (113) is formed, and a fuel gas flow path (123) that is disposed outside the electrolyte-electrode assembly and serves as a flow path for the fuel gas A second separator (120) formed with
The current measuring means (134, 153, 163, 166, 174) measures current at a position closer to the fuel gas outlet (122) than the fuel gas inlet (121) in the fuel gas flow path. 15. The fuel cell system according to any one of claims 7 to 14, wherein:
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