JP2816474B2 - Solid oxide fuel cell module - Google Patents

Description

The present invention relates to a fuel cell using a solid electrolyte,
The present invention relates to a solid oxide fuel cell module having a structure in which a plurality of fuel cells are arranged in a space between an internal current collector and an external current collector tube provided concentrically.

2. Description of the Related Art The output of a solid oxide fuel cell is DC, and the voltage of each fuel cell alone is as low as about 1V. In addition, since the voltage is often converted to AC in practical use, it is desirable that the battery voltage be high also from the viewpoint of conversion efficiency when converting DC to AC. Therefore, it has been necessary to connect a plurality of fuel cells alone in series by some method, and also to connect them in parallel in order to obtain high output.

For example, FIGS. 3 and 4 show the solid oxide fuel cell module described in the applicant's already filed application (Japanese Patent Application No. 1-11433) and the fuel cell unit used therein. The solid oxide fuel cell module 1 shown in FIG. 3 has a space between the inner current collector tube 2 and the outer current collector tube 3 made of a conductive material arranged concentrically with a space therebetween. As shown in FIG. 4, each fuel cell unit 4 contains an oxygen electrode 6 on the inner periphery of a solid electrolyte 5 formed in a cylindrical shape, and The fuel electrode 7 is formed on the outer periphery 3
The fuel cell unit 4 has a layered structure. A slit 8 is formed in the outermost fuel electrode 7 and the intermediate solid electrolyte 5 of the fuel cell unit 4 at a depth reaching the innermost oxygen electrode 6 and parallel to the axis. An interconnector 9 is provided in the slit 8 so as to be in contact with the oxygen electrode 6 and not in contact with the fuel electrode 7.

And each fuel cell unit 4 thus configured is
The tip of each interconnector 9 is brought into contact with the outer peripheral surface of the internal current collector tube 2 via a conductive fiber felt 10, and the outermost fuel electrode 7 of each fuel cell unit 4.
Are brought into contact with the inner peripheral surface of the external current collector tube 3 via the conductive fiber felt 11 and are connected in parallel to form the solid oxide fuel cell module 1.

In the solid oxide fuel cell module 1, oxygen or air is supplied inside the oxygen electrodes 6 of the six fuel cells 4 and the fuel electrodes 7 of the six fuel cells 4 are supplied. A fuel gas such as hydrogen is supplied to a space outside and inside the external current collector tube 3, and an oxidation / reduction reaction occurs through the solid electrolyte 5 to generate electricity. The electricity generated in 4 is collected by the internal current collector tube 2 and the external current collector tube 3 having conductivity.

Problems to be Solved by the Invention In general, a fuel cell needs to isolate a fuel gas flowing on one side of a solid electrolyte from air flowing on the other side with the solid electrolyte 5 interposed therebetween. Then, in a fuel cell of a type in which a plurality of cylindrical combustion cells 4 are assembled as in the above-described conventional solid oxide fuel cell module, the inside of the solid electrolyte 5 of each cylindrical fuel cell 4 is circulated. Has the advantage of being excellent in sealing performance for airtightly separating the fuel gas to be discharged from the air flowing outside the solid electrolyte 5, however, since each fuel cell unit 4 is cylindrical, a plurality of fuel cells are assembled into a solid electrolyte type fuel. When the battery module is configured, there is a disadvantage that a large space is formed between the individual fuel cells. Conventionally, the space formed inside the solid oxide fuel cell module is used only as a flow path for fuel gas or air, and this space has not been sufficiently utilized.

In the case of the above-mentioned conventional solid oxide fuel cell module, it is easy to supply air or fuel gas into each fuel cell 4. In order to supply the fuel gas or the air to the space, it is necessary to connect a fuel gas supply pipe or the like with a pipe, but this connection work is complicated and difficult.

The present invention has been made in view of the above circumstances, and has a main object to effectively use the internal space of a solid oxide fuel cell module using a cylindrical fuel cell alone, and further uses the internal space. To provide an electrolyte fuel cell module that improves the power generation characteristics of the solid oxide fuel cell module and simplifies the connection of the fuel gas supply pipe and the oxygen supply pipe to the solid oxide fuel cell module. It is an object.

Means for Solving the Problems As a means for solving the above-mentioned problems, the present invention provides an inner collector and an outer collector tube provided concentrically with a space, inside a tubular solid electrolyte. In a solid oxide fuel cell module in which an oxygen electrode or a fuel electrode is provided with a plurality of fuel cells each having a fuel electrode or an oxygen electrode on the outside, a space formed between the fuel cells in the external collector tube. In addition, a heat absorbing portion of the heat recovery device is provided.

Further, a fuel in which an oxygen electrode or a fuel electrode is provided inside a tubular solid electrolyte, and a fuel electrode or an oxygen electrode is provided outside, between an internal current collector and an external current collector tube provided concentrically in a space. In a solid-electrolyte fuel cell module in which a plurality of cells are provided, a fuel gas or oxygen supply pipe is provided in a space formed between the fuel cells in the external current collector tube. .

The solid oxide fuel cell module according to claim 1 is
Arranging a heat-absorbing portion of a heat recovery device such as a heat pipe in a space formed around a plurality of fuel cells arranged between concentrically provided internal current collectors and an external current collector tube. As a result, heat of oxidation / reduction reactions in each fuel cell alone is accumulated, and heat is recovered from the inside of the solid oxide fuel cell module when the fuel cell is overheated to a temperature higher than the solid electrolyte temperature where ideal power generation characteristics can be obtained. By taking it out and lowering the temperature inside the module to an appropriate temperature, this was done in the case of the conventional solid oxide fuel cell module,
Increase the supply of fuel gas and air to prevent overheating,
There is no need to perform cooling by exhaust gas, and the consumption of fuel gas and the like is significantly reduced.

Further, the solid oxide fuel cell module according to claim 2 is provided in a space formed around a plurality of fuel cells alone provided between the internal current collector and the external current collector tube provided concentrically. The provision of the fuel gas or air supply pipe eliminates the need for the complicated connection of the fuel gas or air supply pipe at the end of the solid oxide fuel cell module.

Embodiment An embodiment of a solid oxide fuel cell module according to the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 shows a solid oxide fuel cell module 21 according to a first embodiment of the present invention, in which an inner current collector tube 22 and an outer current collector tube 23 provided in a concentric cylindrical shape are disposed between these two. , And six fuel cells 24 connected in parallel.

Each fuel cell unit 24 has a self-supporting structure without using a support tube, and has a solid electrolyte 25 formed of yttria-stabilized zirconia (YSZ) or the like in an annular shape, and is formed inside the solid electrolyte 25. It has a three-layer structure of an oxygen electrode 26 and a fuel electrode 27 formed outside.
Reference numeral 26 denotes a porous body having high conductivity and gas permeability, for example, made of a perovskite-type lanthanum-based composite oxide, and the fuel electrode 27 is formed by solidifying a metal powder such as nickel, or nickel and zirconia. And a porous body such as a cermet. One slit continuous in the longitudinal direction is formed in both the outermost fuel electrode 27 and the solid electrolyte 25 inside thereof, and the interconnector 28 is in contact with the fuel electrode 27 in the slit. It is provided in a state and in contact with the innermost oxygen electrode 26.

Further, each fuel cell unit 24 formed as described above is
The tip of each interconnector 28 is electrically connected to the outer periphery of the internal current collector tube 22 via a nickel felt 29, and is positioned on each fuel electrode 27 so as to face each interconnector 28 with the center therebetween. Are connected to the inner peripheral surface of the external current collector tube 23 via a nickel felt 30 and are arranged in a parallel connection state.

Furthermore, six spaces formed between the fuel cell units 24 disposed between the internal current collecting tube 22 and the external current collecting tube 23 include a space near each external current collecting tube 23 in each space. The evaporator of the heat pipe 31, which is a heat absorbing part of the heat recovery device, is provided in parallel with the fuel cell unit 24, respectively.

Then, air containing oxygen (O ₂ ) is supplied into the hollow portion inside the oxygen electrode 26 of each fuel cell unit 24 constituting the solid oxide fuel cell module 21. The fuel is supplied to the outer periphery of each fuel cell unit 24. The heat recovered from the inside of the solid oxide fuel cell module 21 by each heat pipe 31 is sent to, for example, a steam turbine cycle and used together with the heat of the reaction gas discharged from the downstream side of the external current collector tube 23. .

Next, the operation of this embodiment configured as described above will be described.

In the solid oxide fuel cell module 21, oxygen or air is respectively supplied to the space inside the oxygen electrode 26 of each fuel cell unit 24, and the heat pipe 31 of the heat recovery device around the fuel cell unit 24 is arranged. Hydrogen gas as a fuel is supplied into each space provided, and in each fuel cell unit 24, an oxidation / reduction reaction occurs via each solid electrolyte 25 to generate an electric current, and a nickel felt 29 from each interconnector 28. The internal collector tube 22 that is collected through the anode serves as the anode, and the nickel felt 30
The external current collecting tube 23, which is collected via the IGBT, serves as a cathode, and can take out the generated current.

When the fuel cells 24 in the solid oxide fuel cell module 21 are heated by the reaction heat, the heat is accumulated and the temperature rises to a temperature exceeding the appropriate temperature range of the solid electrolyte 25 performing the oxidation / reduction reaction. Operates the heat recovery device, and the evaporator of each heat pipe 31
It absorbs heat from the atmosphere (fuel gas) inside and transports it to the outside of the solid oxide fuel cell module 21 to form an external current collector tube 23.
The temperature of the inside of the fuel cell is lowered to maintain each fuel cell unit 24 in an appropriate temperature range.

Therefore, since overheating of each fuel cell unit 24 can be prevented, power generation characteristics can be maintained at a high level, continuous operation can be performed for a long time at the upper limit of the power generation capacity, and the temperature inside the solid oxide fuel cell module 21 can be maintained. Management becomes easy. In particular, since the heat pipe 31 is used in the heat absorbing portion of the heat recovery device, the heat recovery device has excellent responsiveness when cooled by the heat recovery device, and can be cooled to a predetermined temperature in a short time.
Further, as compared with the case where the fuel cell alone is cooled by increasing the supply amount of the fuel gas as in the conventional solid oxide fuel cell module, the waste of the fuel gas discharged without participating in the power generation reaction is reduced. Consumption can be significantly reduced.

The heat recovered by the heat recovery device is used, for example, to preheat fuel gas or the like supplied to the solid oxide fuel cell module 21, or is discharged from the downstream side of the external current collector tube 23 to be used as an afterburner. Along with the heat of the exhaust gas combusted in the above, it is sent to a steam turbine cycle or the like for use.

FIG. 2 shows a second embodiment of the present invention. This solid electrolyte fuel cell module 41 is the same as the solid electrolyte fuel cell module 21 of the first embodiment, except that the inner current collector tube 22 and the outer current collector tube are different from each other. Of the six heat pipes 31 arranged in the space around each fuel cell unit 24 provided between the heat pipes 23 and 23, a total of three heat pipes 31 are eliminated every other one, and the heat pipes 31 are removed. The fuel gas supply pipe 42 is provided instead of each position except for the following. The same reference numerals are given to the same components as those in the first embodiment, and the detailed description of those portions will be omitted. explain.

Internal collector tube 22 of solid oxide fuel cell module 41
And six fuel cells 24 between the external current collector tube 23 and
The tip of each interconnector 28 is located on the outer periphery of the internal current collector tube 22 via a nickel felt 29, and the position facing each interconnector 28 with the center on each fuel electrode 27 via a nickel felt 30. It is arranged in a state of being connected to the inner peripheral surface of the external current collector tube 23 and connected in parallel.

And, in the six spaces formed between the individual fuel cells 24 in the external current collector tube 23, three heat pipes 31 which are heat absorbing portions of the heat recovery device and three fuel gas supply pipes are provided. The terminals 42 are provided in parallel with the fuel cell unit 24, and the heat pipes 31 and the supply pipe terminals 42 are alternately arranged alternately.

In the solid oxide fuel cell module 41, air is supplied into the hollow portion of each fuel cell unit 24, and the space around the fuel cell unit 24 in the external current collector tube 23 is provided in this space. Further, hydrogen of the fuel gas is supplied from the supply pipe terminal 42. Therefore, supply pipe terminal
A large number of holes are formed in the section disposed in the space of 42 and fuel gas is ejected from these holes, or the external current collector tube 23 is made to be a closed end type, and the supply tube terminal 42 If the front end is disposed near the bottom of the external current collector tube 23 that closes the front end, and the fuel gas is ejected from the front end of the supply tube terminal 41, the fuel gas supply tube and the external current collector tube 23 There is no need for a pipe connection for airtight connection with the like.

The heat pipe 31 of the heat recovery device recovers heat from inside the solid oxide fuel cell module 41 when each fuel cell unit 24 becomes overheated, lowers the temperature of the fuel cell unit 24, and The range is returned to maintain the power generation characteristics at a high level.

Next, the operation of the second embodiment configured as described above will be described.

In the solid oxide fuel cell module 41, air is supplied to the space inside the oxygen electrode 26 of each fuel cell unit 24, and the heat pipe 31 and the heat pipe 31 are arranged alternately in the space around the fuel electrode 27. Hydrogen gas is supplied from each of the supply pipe terminals 42 provided, and in each fuel cell unit 24, an oxidation / reduction reaction occurs via the respective solid electrolyte 25 to generate a current, and a nickel felt 29 from each interconnector 28.
The internal collector tube 22 that is collected through the anode serves as an anode, and the outer collector tube 23 that is collected from each outer peripheral fuel electrode 27 through the nickel felt 30 serves as a cathode, and the generated current can be taken out. it can. Further, as described above, in particular, a large number of holes are formed in the supply tube terminal 42 so that the fuel gas is uniformly supplied to the entire length direction of each fuel cell unit 24, or the external current collector tube 23 is closed at the end. As a result, the fuel gas is ejected to the closed front end side in the external current collector tube 23 to reverse the flow direction and diffuse the fuel gas, so that the fuel gas is supplied uniformly throughout the external current collector tube 23, thereby improving the power generation characteristics. be able to.

Further, each fuel cell unit 24 in the solid oxide fuel cell module 41 is heated by the reaction heat, and when the heat is accumulated and becomes overheated, the heat recovery device is activated to operate each heat pipe 31. Absorbs heat from the atmosphere (fuel gas) in the external current collector tube 23 and transports the heat to the outside of the solid oxide fuel cell module 41, lowers the ambient temperature in the external current collector tube 23, and Is maintained in an appropriate temperature range, the power generation characteristics of each fuel cell unit 24 can be maintained at a high level, and continuous operation for a long time is possible with the upper limit of the power generation capacity. Further, the temperature control in the solid oxide fuel cell module 41 is facilitated, and in particular, since the heat pipe 31 is used in the heat absorbing portion of the heat recovery device, the responsiveness when cooling by the heat recovery device is excellent, It can be cooled to a predetermined temperature in a short time. Furthermore, as compared with the case of cooling the fuel cell alone by increasing the supply amount of the fuel gas as in the conventional solid oxide fuel cell module, the waste of the fuel gas discharged without participating in the power generation reaction is reduced. Consumption can be significantly reduced.

The heat recovered by the heat recovery device is transferred to the external current collector tube 23.
The exhaust gas is discharged from the downstream side and is sent to, for example, a steam turbine cycle and used together with the heat of the exhaust gas burned by the afterburner.

Effect of the Invention As described above, the present invention provides an oxygen electrode or a fuel electrode inside a tubular solid electrolyte between an internal current collector and an external current collector tube provided concentrically with a space, and an outer electrode. In a solid oxide fuel cell module in which a plurality of fuel cells each having a fuel electrode or an oxygen electrode are provided,
Since the heat absorbing portion of the heat recovery device is disposed in the space formed between the individual fuel cells in the external current collector tube, the space in the solid oxide fuel cell module can be effectively used, and Overheating can be prevented to maintain the power generation characteristics at a high level, and the excess heat energy recovered by the heat recovery device can be effectively used.

Further, an oxygen electrode or fuel electrode was provided inside the tubular solid electrolyte, and a fuel electrode or oxygen electrode was provided outside the tubular solid electrolyte between the internal current collector tube and the external current collector tube provided concentrically in a space. In a solid oxide fuel cell module in which a plurality of fuel cells are provided, a fuel gas or oxygen supply pipe is provided in a space formed between the fuel cells in the external current collector tube. The effective use of the space in the fuel cell module can be achieved, and there is an effect that piping connection for airtightly connecting the end of the external current collector tube and the fuel gas or oxygen supply tube becomes unnecessary.

[Brief description of the drawings]

1 and 2 each show an embodiment of the present invention. FIG. 1 is a sectional front view of a solid oxide fuel cell module according to the first embodiment, and FIG. 2 is a solid electrolyte according to the second embodiment. 3 and 4 show a conventional example, and FIG. 3 is a cross-sectional front view of a conventional solid oxide fuel cell module, and FIG. 4 is a solid oxide fuel cell. FIG. 2 is a perspective view of a single fuel cell constituting a module. 21,41… solid electrolyte type fuel cell module, 22… internal collector tube, 23… external collector tube, 24… fuel cell unit, 25… solid electrolyte, 26… oxygen electrode, 27… fuel electrode , 28 ... interconnector, 29, 30 ... nickel felt, 31 ... heat pipe, 42 ... fuel gas supply pipe terminal.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shoichi Hasegawa 1-5-1 Kiba, Koto-ku, Tokyo Fujikura Electric Wire Co., Ltd. (72) Inventor Masayuki Tan 1-1-5-1 Kiba, Koto-ku, Tokyo Fujikura (72) Inventor Hiroshi Yamanouchi 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric Wire Co., Ltd. (56) References JP-A-62-274562 (JP, A) (58) Fields investigated ( Int.Cl. ⁶ , DB name) H01M 8/00-8/02 H01M 8/04 H01M 8/08-8/24

Claims (2)

(57) [Claims] An oxygen electrode or a fuel electrode is provided inside a tubular solid electrolyte, and a fuel electrode or an oxygen electrode is provided outside a tubular solid electrolyte between an internal current collector and an external current collector tube provided concentrically with a space. In a solid oxide fuel cell module in which a plurality of the provided fuel cells are provided, a heat absorbing portion of a heat recovery device is provided in a space formed between the fuel cells in the external current collector tube. Solid electrolyte fuel cell module. 2. An oxygen electrode or fuel electrode inside a tubular solid electrolyte, and a fuel electrode or oxygen electrode outside a tubular solid electrolyte, between an internal current collector and an external current collector tube provided concentrically with a space. In a solid oxide fuel cell module in which a plurality of the provided fuel cells are provided, a fuel gas or oxygen supply pipe is provided in a space formed between the fuel cells in the external current collector tube. Characteristic solid electrolyte fuel cell module.