JP7029122B2 - Fuel cell system - Google Patents

Description

The present invention relates to a fuel cell system using a proton conduction type solid oxide.

Conventionally, a solid oxide fuel cell (SOFC) using oxygen ions ( ^O2- ) as conduction ions has been widely used. However, the conventional SOFC has a problem that the concentration of the fuel decreases because water is generated on the fuel electrode (anode) side.

Therefore, a proton-conducting ceramic-electrolyte fuel cell (PCFC) that uses a proton-conducting solid oxide that uses protons (H ⁺ ) as conduction ions as a solid electrolyte is used as a next-generation fuel cell. It is attracting attention (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2016-100196

However, the efficient operating conditions of PCFC have not been clarified.

In view of such problems, it is an object of the present invention to provide a fuel cell system capable of efficiently operating a fuel cell using a proton conduction type solid oxide.

In order to solve the above problems, the fuel cell system according to the present invention is provided separately from the fuel electrode and the fuel cell, and has BaZrCeYXO _3-δ (however, X = Sc, Ga, In, Gd, and , Yb , a fuel cell body having a three-layer structure consisting of a solid electrolyte containing a solid oxide represented by (1) or (a plurality), and an air electrode provided separately from the solid electrolyte, and the fuel cell. The product of the temperature control unit that keeps the main body at 400 ° C or higher and lower than 700 ° C, the thickness of the solid electrolyte, and the current density of the fuel cell main body is 12.5 μm · A / cm ² or more and 25 μm · A / cm ² or less . With the control unit to maintain
To prepare for.

Further, the X may be either one or both of Gd and Yb.

Further, a reformer for reforming either one or both of hydrocarbons and alcohol to hydrogen is further provided, the reformer is heated by the fuel cell main body, and the temperature adjusting unit uses the fuel cell main body. It may be 500 ° C. or higher and lower than 700 ° C.

Further , the control unit determines the amount of hydrogen supplied to the fuel electrode and the temperature control unit so as to maintain the multiplication value at 12.5 μm · A / cm ² or more and 25 μm · A / cm ² or less . Either one or both may be controlled.

According to the present invention, it is possible to efficiently operate a fuel cell using a proton conduction type solid oxide.

It is a figure explaining the fuel cell system. It is a figure explaining the ion which conducts a solid electrolyte. It is a figure explaining the change of the ion transport number of the BZCYX electrolyte with respect to the oxygen partial pressure. It is a figure explaining the temperature dependence of the ionic conductivity of a BZCYX electrolyte. It is a figure explaining the relationship between the current density of a fuel cell main body, and a leak current. It is a figure explaining the relationship between the current density of a fuel cell main body, and a fuel utilization rate. It is a figure explaining the relationship between the current density of a fuel cell main body, and power generation efficiency η [%].

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, other specific numerical values, etc. shown in the embodiment are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and the drawings, elements having substantially the same function and configuration are designated by the same reference numerals to omit duplicate explanations, and elements not directly related to the present invention are not shown. do.

(Fuel cell system 100)
FIG. 1 is a diagram illustrating a fuel cell system 100. In FIG. 1, the gas flow is indicated by a solid arrow, and the control signal flow is indicated by a broken line arrow.

As shown in FIG. 1, the fuel cell system 100 includes a fuel cell unit 110 and a control unit 120.

(Fuel cell unit 110)
The fuel cell unit 110 includes a fuel cell module 210, a blower 220, and a temperature adjusting unit 230. The fuel cell module 210 includes a reformer 212 and a fuel cell body 214.

The reformer 212 contains a catalyst that promotes the steam reforming reaction of hydrocarbons. The reformer 212 is heated to a predetermined temperature by the fuel cell main body 214 described later. The reformer 212 is connected to the fuel supply pipe 212a, and hydrocarbons ( _{Cn Hm} , for example, city gas) and steam are supplied through the fuel supply pipe 212a. The fuel supply pipe 212a is provided with a flow rate adjusting valve 212b.

When hydrocarbon and steam are supplied to the reformer 212, the steam reforming reaction represented by the following reaction formulas (1) and ( ₂ ) proceeds, and the hydrocarbon becomes hydrogen (H2) or carbon monoxide (H2). It is reformed to CO).
C _n H _m + nH ₂ O → nCO + (m / 2 + n) H ₂ … Reaction equation (1)
CO + H ₂ O → CO ₂ + H ₂ … Reaction equation (2)

In this way, the reformer 212 produces hydrogen (hereinafter referred to as “fuel”). Then, the fuel generated by the reformer 212 is supplied to the fuel electrode 214a of the fuel cell main body 214.

The blower 220 supplies an oxygen-containing gas (for example, air) to the air electrode 214b of the fuel cell main body 214.

The fuel cell main body 214 (cell stack) is a proton conduction type fuel cell (PCFC). The fuel cell main body 214 includes a fuel electrode 214a, an air electrode 214b, and a solid electrolyte 214c.

The fuel electrode 214a (anode) is composed of, for example, nickel (Ni) and zirconia (Zr). The air electrode 214b (cathode) is configured to include, for example, lanthanum manganite (LSM).

The solid electrolyte 214c is composed of a proton-conducting solid oxide. The fuel cell body 214 having the solid electrolyte 214c containing a proton-conducting solid oxide mainly conducts protons (H ⁺ ) as ions. Therefore, when fuel is supplied to the fuel electrode 214a, the oxidation reaction represented by the following reaction formula (3) proceeds, and when air is supplied to the air electrode 214b, the reduction reaction represented by the following reaction formula (4) proceeds. Progresses. Then, the proton conducts (moves) the solid electrolyte 214c, so that the fuel cell main body 214 generates electricity. That is, the fuel cell main body 214 generates electricity from fuel and oxygen.
H ₂ → 2H ⁺ + 2e -... Reaction equation ⁽ 3)
1 / 2O ₂ + 2H ⁺ + ^2e- → H ₂ O… Reaction equation (4)

Further, in the fuel cell main body 214, heat is generated when the reactions represented by the above reaction formulas (3) and (4) proceed and power generation is performed.

In the present embodiment, the proton conduction type solid oxide is an oxide represented by BaZrCeYXO _3-δ (whereever, one or more of X = Sc, Ga, In, Gd, and Yb). Preferably, X is one or both of Gd and Yb. In addition, each element (Ba, Zr, Ce, Y, Sc, Ga, In, Gd, in any one or more of X = Sc, Ga, In, Gd, and Yb) in BaZrCeYXO _3-δ (where X = Sc, Ga, In, Gd, and Yb) The content of Yb) is not limited.

By including BaZrCeYXO _3-δ (whereever one or more of X = Sc, Ga, In, Gd, and Yb), the solid electrolyte 214c is an oxide ion-conducting solid oxide (eg, one or more). Compared with the conventional fuel cell body (conventional SOFC) equipped with a solid electrolyte containing YSZ (yttria-stabilized zirconia), it is possible to prevent the concentration of fuel in the fuel electrode 214a from decreasing and improve power generation efficiency. It is possible to make it.

Further, since the solid electrolyte 214c contains BaZrCeYXO _3-δ (however, one or more of X = Sc, Ga, In, Gd, and Yb), power is generated at a lower temperature than that of the conventional SOFC. It is possible to make it.

Further, by adopting BaZrCeYXO _3-δ (however, one or more of X = Sc, Ga, In, Gd, and Yb) as the proton conduction type solid oxide, BaZrCeYO 3- _δ can be obtained. In comparison, chemical stability can be improved.

Further, the solid electrolyte 214c contains BaZrCeYXO _3-δ (however, X = Gd and / or both of X = Gd), so that the power generation efficiency can be further improved.

The temperature control unit 230 is composed of a semiconductor integrated circuit including a CPU (Central Processing Unit). The temperature control unit 230 reads out a program, parameters, and the like for operating the CPU itself from the ROM. The temperature control unit 230 controls the blower 220 in cooperation with the RAM as a work area and other electronic circuits. In the present embodiment, the temperature adjusting unit 230 is the air supplied by the blower 220 so that the fuel cell main body 214 (fuel cell module 210) is 400 ° C. or higher and lower than 700 ° C., preferably 500 ° C. or higher and lower than 700 ° C. Adjust the amount.

FIG. 2 is a diagram illustrating an ion conducting the solid electrolyte 214c. As described above, the solid electrolyte 214c containing the proton-conducting solid oxide mainly conducts protons (H ⁺ ). Further, as shown in FIG. 2, the solid electrolyte 214c conducts oxygen ions (O ^2- ), electrons (e ⁻ ), and holes (h ⁺ ) in addition to protons. Here, the conduction of holes causes a leakage current (leakage current) in the solid electrolyte 214c, which causes a decrease in energy efficiency and output of the fuel cell main body 214.

Therefore, the temperature and oxygen partial pressure of the solid electrolyte containing BaZrCeYXO _3-δ (hereinafter referred to as “BZCYX electrolyte”) were changed to derive the ion transport number. Specifically, the BZCYX electrolyte is housed in an electric furnace and maintained at a predetermined temperature (550 ° C, 600 ° C, 700 ° C), and the oxygen of the gas supplied to the electric furnace is measured while measuring the conductivity of the BZCYX electrolyte. The partial pressure was changed. Then, the ion transport number was derived from the measured conductivity.

FIG. 3 is a diagram illustrating a change in the ion transport number of the BZCYX electrolyte with respect to the partial pressure of oxygen. 3 (a) and 3 (b) show the case where the BZCYX electrolyte is set to 550 ° C. 3 (c) and 3 (d) show the case where the BZCYX electrolyte is set to 600 ° C. 3 (e) and 3 (f) show the case where the BZCYX electrolyte is set to 700 ° C.

In FIGS. 3 (a), 3 (c), and 3 (e), X = Ga is indicated by a black circle, X = In is indicated by a black triangle, and X = Yb is indicated by a white triangle. In FIGS. 3 (b), 3 (d), and 3 (f), X = Sc is indicated by a white square and X = Gd is indicated by a white circle. Further, in FIGS. 3 (a) to 3 (f), the vertical axis represents the ion transport number and the horizontal axis represents the oxygen partial pressure (log (PO ₂ [atm])). That is, the horizontal axis corresponds to the thickness direction of the solid electrolyte 214c, the direction toward the right side (the side with a large oxygen partial pressure) is the direction toward the air electrode 214b, and the direction toward the left side (the side with a small oxygen partial pressure). Is in the direction of approaching the fuel electrode 214a.

3 (a) As shown in FIG. 3 (b), when X in the BZCYX electrolyte is Ga, Sc, and In at 550 ° C., the ion transport number hardly decreases even if the oxygen partial pressure increases. On the other hand, when X in the BZCYX electrolyte was Yb and Gd, it was found that the ion transport number decreased as the oxygen partial pressure increased.

Further, as shown in FIGS. 3 (c) and 3 (d), at 600 ° C., even when X in the BZCYX electrolyte is Ga, Sc, and In, the ion transport number increases as the oxygen partial pressure increases. Was confirmed to decrease slightly. Further, it was found that when X in the BZCYX electrolyte was Yb and Gd, the ion transport number decreased as the oxygen partial pressure increased as compared with the case where X was Ga, Sc and In.

Further, as shown in FIGS. 3 (e) and 3 (f), at 700 ° C., the ion transport number may decrease sharply as the oxygen partial pressure increases, regardless of the element X in the BZCYX electrolyte. confirmed.

From the above experimental results, it was found that the ion transport number of the BZCYX electrolyte significantly decreased at 700 ° C. or higher. That is, it was confirmed that the BZCYX electrolyte rapidly increases the conduction of holes when the temperature rises above 700 ° C.

That is, when the fuel cell main body 214 is 700 ° C. or higher, the ion transport number is lower than when the temperature is lower than 700 ° C. Therefore, by setting the temperature of the fuel cell main body 214 to less than 700 ° C. by the temperature adjusting unit 230, the power generation efficiency of the fuel cell main body 214 can be improved.

Further, from the above experimental results, it was confirmed that the lower the temperature, the higher the ion transport number of the BZCYX electrolyte. However, if the temperature is too low, the ionic conductivity of the BZCYX electrolyte will decrease. Therefore, the ionic conductivity of the BZCYX electrolyte was measured while changing the temperature.

FIG. 4 is a diagram illustrating the temperature dependence of the ionic conductivity of the BZCYX electrolyte. In FIG. 4, the vertical axis is the ionic conductivity (log (σ [Scm ^-1 ])), and the horizontal axis is the temperature (1000 / T [K], [° C.]). Note that FIG. 4 shows the ionic conductivity of the BZCYX electrolyte when X is Gd.

As shown in FIG. 4, it was found that the ionic conductivity of the BZCYX electrolyte decreased as the temperature decreased. Further, even at 400 ° C., the ionic conductivity of the BZCYX electrolyte is an index of high-efficiency operation of the fuel cell main body 214, which is 5 × 10 ^-3 Scm ^-1 (≈-2.3 (log (σ [Scm ⁻ )). ¹ ]))) It was confirmed that the above was the case.

Therefore, by maintaining the fuel cell main body 214 at 400 ° C. or higher by the temperature adjusting unit 230, the power generation efficiency of the fuel cell main body 214 can be set to a predetermined value or higher.

Further, as described above, the fuel cell main body 214 heats the reformer 212. When the temperature of the fuel cell main body 214 is lower than 500 ° C, the reaction of the steam reforming reaction (reaction formula (1), reaction formula (2)) in the reformer 212 is compared with the case where the temperature is 500 ° C or higher. Low efficiency. Therefore, by setting the temperature of the fuel cell main body 214 to 500 ° C. or higher by the temperature adjusting unit 230, the reaction efficiency of the steam reforming reaction in the reformer 212 can be improved. That is, it is possible to increase the amount of fuel produced in the reformer 212.

(Control unit 120)
Returning to FIG. 1, the control unit 120 (power conditioner) is composed of a semiconductor integrated circuit including a CPU (central processing unit). The control unit 120 reads out a program, parameters, and the like for operating the CPU itself from the ROM. The control unit 120 manages and controls the entire fuel cell system 100 in cooperation with RAM as a work area and other electronic circuits. The control unit 120 takes out DC power from the fuel cell main body 214, converts it into AC power, and supplies it to the load.

Further, in the present embodiment, the control unit 120 controls one or both of the flow rate adjusting valve 212b and the temperature adjusting unit 230. Specifically, the control unit 120 controls one or both of the flow rate adjusting valve 212b and the temperature adjusting unit 230 so that the current density of the fuel cell main body 214 becomes a predetermined value.

The leakage current when the current density of the generated current of the fuel cell main body 214 (hereinafter, simply referred to as “current density”) was increased was measured. Further, the fuel utilization rate Uf [%] when the current density of the fuel cell main body 214 was increased was calculated. Further, based on the leak current and the fuel utilization rate Uf, the relationship between the current density of the fuel cell main body 214 and the power generation efficiency η [%] was derived. The thickness (distance and film thickness between the fuel electrode 214a and the air electrode 214b) of the solid electrolyte 214c in the fuel cell main body 214 was set to 25 μm.

FIG. 5 is a diagram illustrating the relationship between the current density of the fuel cell main body 214 and the leak current. FIG. 5A shows a case where the fuel cell main body 214 is set to 550 ° C. FIG. 5B shows a case where the fuel cell main body 214 is set to 600 ° C. FIG. 5C shows a case where the fuel cell main body 214 is set to 700 ° C. In FIGS. 5 (a) to 5 (c), the vertical axis is the ratio of the leak current density to the generated current density (i _leak / i _ext ), and the horizontal axis is the current density (i _ext [Acm ^-2 ]). ..

FIG. 6 is a diagram illustrating the relationship between the current density of the fuel cell main body 214 and the fuel utilization rate Uf. FIG. 6A shows a case where the fuel cell main body 214 is set to 550 ° C. FIG. 6B shows a case where the fuel cell main body 214 is set to 600 ° C. FIG. 6C shows a case where the fuel cell main body 214 is set to 700 ° C. In FIGS. 6 (a) to 6 (c), the vertical axis is the fuel utilization rate Uf [%], and the horizontal axis is the current density ( _ext [Acm ^-2 ]).

FIG. 7 is a diagram illustrating the relationship between the current density of the fuel cell main body 214 and the power generation efficiency η [%]. FIG. 7A shows a case where the fuel cell main body 214 is set to 550 ° C. FIG. 7B shows a case where the fuel cell main body 214 is set to 600 ° C. FIG. 7C shows a case where the fuel cell main body 214 is set to 700 ° C. In FIGS. 7 (a) to 7 (c), the vertical axis represents the power generation efficiency η [%], and the horizontal axis represents the current density ( _ext [Acm ^-2 ]).

In FIGS. 5 (a) to 5 (c), FIGS. 6 (a) to 6 (c), and FIGS. 7 (a) to 7 (c), X = Ga is a black circle and X = Sc. In a white square, X = In is indicated by a black triangle, X = Yb is indicated by a white triangle, and X = Gd is indicated by a white circle. Further, in FIGS. 6 (a) to 6 (c) and 7 (a) to 7 (c), the values of the conventional SOFC using YSZ are shown by broken lines.

(About leak current)
As shown in FIGS. 5A to 5C, it was confirmed that the leakage current decreases as the current density increases, regardless of the temperature of the fuel cell main body 214.

(About fuel utilization rate Uf)
When the fuel cell main body 214 is at 550 ° C., as shown in FIG. 6A, when the X of the BZCYX electrolyte of the solid electrolyte 214c is Sc and In, the fuel utilization rate Uf is conventional regardless of the current density. It was the same as SOFC (about 75%). On the other hand, when the X of the BZCYX electrolyte of the solid electrolyte 214c is Yb and Gd, it was confirmed that the fuel utilization rate Uf increases as the current density increases. When X is Yb, the fuel utilization rate Uf is 70% or more when the current density is 0.35 Acm ^-2 or more, and the same as the conventional SOFC when the current density is 0.75 Acm ^-2 or more. It was found that the fuel utilization rate was about Uf. On the other hand, when X is Gd, the fuel utilization rate Uf is 70% or more when the current density is 0.5 Acm ^-2 or more, and the same as the conventional SOFC when the current density is 1.0 Acm ^-2 or more. It was confirmed that the fuel utilization rate was about Uf.

When the fuel cell body 214 is at 600 ° C. and the X of the BZCYX electrolyte of the solid electrolyte 214c is Ga, as shown in FIG. 6B, the fuel utilization rate Uf is the same as that of the conventional SOFC (about 75%). )Met. On the other hand, when the X of the BZCYX electrolyte of the solid electrolyte 214c is Sc, In, Yb, and Gd, it was confirmed that the fuel utilization rate Uf increases as the current density increases. When X is Sc or In, the fuel utilization rate Uf is 70% or more when the current density is 0.25 Acm ^-2 or more, and the conventional SOFC is when the current density is 0.35 Acm ^-2 or more. It was found that the fuel utilization rate was about the same as Uf. On the other hand, when X is Yb, the fuel utilization rate Uf is 70% or more when the current density is 0.5 Acm ^-2 or more, and the same as the conventional SOFC when the current density is 1.0 Acm ^-2 or more. It was found that the fuel utilization rate was about Uf. When X is Gd, the fuel utilization rate Uf is 70% or more when the current density is 0.75 Acm ^-2 or more, and the same as the conventional SOFC when the current density is 1.0 Acm ^-2 or more. It was confirmed that the fuel utilization rate was about Uf.

Further, when the fuel cell main body 214 is at 700 ° C. and the X of the BZCYX electrolyte of the solid electrolyte 214c is Ga as shown in FIG. 6 (c), the fuel utilization rate Uf is the same as that of the conventional SOFC (75). %). On the other hand, when the X of the BZCYX electrolyte of the solid electrolyte 214c is Sc, In, Yb, and Gd, it was confirmed that the fuel utilization rate Uf increases as the current density increases. When X is Sc or In, the fuel utilization rate Uf is 70% or more when the current density is 0.5 Acm ^-2 or more, and the conventional SOFC is when the current density is 0.75 Acm ^-2 or more. It was found that the fuel utilization rate was about the same as Uf. On the other hand, when X is Yb, the fuel utilization rate Uf is 60% or more when the current density is 0.75 Acm ^-2 or more, and the fuel utilization rate Uf is 1.0 Acm -2 or more when the current density is 1.0 Acm ^-2 or more. It turned out to be about 68%. Further, it was confirmed that when X is Gd and the current density is 1.0 Acm ^-2 or more, the fuel utilization rate Uf is about 64%.

(About power generation efficiency η)
As shown in FIGS. 7 (a) to 7 (c), in the conventional SOFC, when the current density is increased, the internal resistance increases and the power generation efficiency η decreases. On the other hand, in the fuel cell main body 214, although the internal resistance increases when the current density is increased, the leakage current decreases as shown in FIGS. 5 (a) to 5 (c), and the above-mentioned FIG. 6 As shown in FIGS. 6 (a) to 6 (c), the fuel utilization rate Uf increases, so that the power generation efficiency η increases.

Specifically, as shown in FIG. 7A, when the fuel cell main body 214 is at 550 ° C. and the X of the BZCYX electrolyte of the solid electrolyte 214c is Sc and In, power is generated as the current density increases. Although the efficiency η is reduced, the power generation efficiency η is higher than that of the conventional SOFC. On the other hand, when the X of the BZCYX electrolyte of the solid electrolyte 214c is Yb and Gd, the power generation efficiency η increases as the current density increases up to a current density of about 0.5 Acm ^-2 , and the current density becomes 0.5 Acm ⁻ . It was confirmed that a high power generation efficiency η was maintained at ² or more. It was also found that when the current density was 0.5 Acm ^-2 or more, the power generation efficiency η was about 68%.

Further, as shown in FIG. 7B, when the fuel cell main body 214 is at 600 ° C. and the X of the BZCYX electrolyte of the solid electrolyte 214c is Sc and In, the power generation efficiency η decreases as the current density increases. However, the power generation efficiency was higher than that of the conventional SOFC. On the other hand, when the X of the BZCYX electrolyte of the solid electrolyte 214c is Yb and Gd, the power generation efficiency η increases as the current density increases up to a current density of about 0.5 Acm ^-2 , and the current density becomes 0.5 Acm ⁻ . It was confirmed that a high power generation efficiency η was maintained at ² or more. It was also found that when the current density was 0.5 Acm ^-2 or more, the power generation efficiency η was about 68%.

On the other hand, as shown in FIG. 7C, when the fuel cell main body 214 is at 700 ° C., the power generation efficiency η increases as the current density increases except for X being Ga and In, but the power generation is higher than that of the conventional SOFC. It was confirmed that the efficiency was low.

From the above experimental results, the control unit 120 has a flow rate such that when the thickness of the solid electrolyte 214c is 25 μm, the current density (current density of the generated current) of the fuel cell main body 214 is 0.5 A / cm ² or more. By controlling one or both of the control valve 212b and the temperature control unit 230, it is possible to realize a power generation efficiency η higher than that of the conventional SOFC. That is, the control unit 120 has a flow rate adjusting valve 212b so that the product of the thickness of the solid electrolyte 214c and the current density of the fuel cell main body 214 (current density of the generated current) is 12.5 μm · A / cm ² or more. , And one or both of the temperature control unit 230 are controlled. This makes it possible to operate the fuel cell main body 214 with a higher power generation efficiency η as compared with the conventional SOFC.

Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such an embodiment. It is clear that a person skilled in the art can come up with various modifications or modifications within the scope of the claims, which naturally belong to the technical scope of the present invention. Understood.

For example, in the above embodiment, the configuration in which the hydrocarbon is supplied to the reformer 212 has been described as an example. However, alcohol (eg, bioethanol) may be supplied to the reformer 212. In this case, the reformer 212 contains a catalyst that promotes steam reforming of alcohol.

Further, in the above embodiment, the configuration in which the fuel cell module 210 includes the reformer 212 will be described as an example. However, the reformer 212 is not an essential configuration. For example, hydrogen may be directly supplied from the hydrogen source to the fuel electrode 214a of the fuel cell main body 214.

Further, in the above embodiment, the temperature adjusting unit 230 has been described by taking as an example a configuration in which the blower 220 is controlled so that the temperature of the fuel cell main body 214 is set to 400 ° C. or higher and lower than 700 ° C. However, even if the temperature adjusting unit 230 is composed of a heat exchanger that exchanges heat between the air supplied to the air electrode 214b (air discharged from the blower 220) and the exhaust gas exhausted from the fuel cell main body 214. good. In this case, the temperature adjusting unit 230 preheats the air and cools the exhaust gas to bring the temperature of the fuel cell main body 214 to 400 ° C. or higher and lower than 700 ° C.

The present invention can be applied to a fuel cell system using a proton conduction type solid oxide.

100 Fuel cell system 110 Fuel cell unit 120 Control unit 210 Fuel cell module 212 Reformer 214 Fuel cell body 214c Solid electrolyte 230 Temperature control unit

Claims (4)

A solid oxide which is provided separately from the fuel electrode and the fuel electrode and is represented by BaZrCeYXO _3-δ (provided that one or more of X = Sc, Ga, In, Gd, and Yb) is used. A fuel cell body having a three-layer structure consisting of a solid electrolyte containing the solid electrolyte and an air electrode provided separately from the solid electrolyte .
A temperature control unit that keeps the fuel cell body at 400 ° C or higher and lower than 700 ° C,
A control unit that maintains the multiplication value of the thickness of the solid electrolyte and the current density of the fuel cell body at 12.5 μm · A / cm ² or more and 25 μm · A / cm ² or less .
A fuel cell system equipped with. The fuel cell system according to claim 1, wherein X is one or both of Gd and Yb. Further equipped with a reformer that reforms one or both of hydrocarbons and alcohol to hydrogen,
The reformer is heated by the fuel cell body and is heated.
The fuel cell system according to claim 1 or 2, wherein the temperature adjusting unit keeps the fuel cell body at 500 ° C. or higher and lower than 700 ° C. The control unit is either the amount of hydrogen supplied to the fuel electrode or the temperature control unit so as to maintain the multiplication value at 12.5 μm · A / cm ² or more and 25 μm · A / cm ² or less . The fuel cell system according to any one of claims 1 to 3, wherein one or both of them are controlled.

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