JPH0665045B2 - Fuel cell - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fuel cell, and more particularly to a fuel cell used as a power source of small output.

[Prior Art] A fuel cell is a device that generates electricity by an electrochemical reaction between a fuel supplied from the outside and an oxidant. Basically, a fuel side electrode and a cathode that are anodes separated by an electrolyte. The fuel gas and the oxidant gas are supplied to both electrodes by the gas separation plate.

FIG. 5 is a sectional view showing a conventional unit cell (6). In the figure, (1) is a fuel-side electrode base material, and (2) is a fuel-side electrode base material.
(1) a fuel-side catalyst layer provided on one surface, (3) is an electrolyte holder, for example, an electrolyte-holding matrix, (4) is one surface of the oxidant-side electrode substrate (5), the electrolyte-holding matrix (3)
Is a catalyst layer on the oxidant side opposite to the above. Further, FIG. 6 shows a cross-sectional view of a fuel cell in which unit cells (6) and gas separation plates (7) are alternately laminated, and in this case, four fuel cells (6) are formed. In the figure, (8) is an oxidant gas flow path,
(9) is a fuel gas flow path, and (10) is a current collector plate. Gas separation plate
(7) is composed of an electronically conductive material, the oxidant gas flow channel (8) and the fuel gas flow channel (9) for supplying the oxidant gas and the fuel gas to the unit cell (6) It is provided. The oxidant gas flow channel (8) and the fuel gas flow channel (9) are respectively formed on parallel planes and are configured to be orthogonal to each other when seen through.

Next, the operation will be described. In the single cell (6), the fuel gas is supplied to the fuel-side electrode substrate (1) from the fuel gas channel (9) of the gas separation plate (7), and the three-phase interface in the fuel-side catalyst layer (2) React with. Similarly, the oxidant gas is supplied from the oxidant gas flow channel (8) to the oxidant side electrode base material (5), and a reaction occurs at the three-phase interface in the oxidant side catalyst layer (4). When this reaction occurs, ions move in the electrolyte holding matrix (3), and charges are exchanged between the electrode base materials (1) and (5) to generate an electromotive force. The gas separating plate (7) functions not only to supply the reaction gas to the unit cells (6) but also to electrically connect the stacked upper and lower unit cells (6) in series. In FIG. 6, four unit cells (6) are connected in series by the gas separating plate (7), and the generated electricity is collected by the current collecting plate (10) and connected to the external load.

The above fuel cell is used as a power source. However, the obtained voltage is direct current, and power consumption in factories and homes is two-phase or three-phase alternating current of 100 to 220V. Therefore, the electric power obtained from the fuel cell is converted into alternating current through the inverter, but a direct current voltage of at least 60 V or more is required to improve the conversion efficiency in the inverter. However, the output voltage of the fuel cell is 0.6 to 0.8V per cell, and 8 to obtain 60V.
A stack of 0-100 cells is required. The thickness of the unit cell (6) including the gas separation plate (7) is limited to 5 mm no matter how thin the cell is. Further, it is necessary to insert a cooler for every several cells of a single battery in order to control the operating temperature. Therefore, the height becomes 1 to 2 m in order to obtain an output of 60 V, which is too large to be easily used as a small output power source, as well as a large output power source.

[Problems to be solved by the invention]

Since the conventional fuel cell is configured as described above, the height must be increased in order to obtain a predetermined voltage, and the external shape is too large to be easily used as a power source of small output. There was a point.

The present invention has been made to solve the above-mentioned problems, and it is possible to obtain a predetermined voltage without increasing the height, and it is suitable as a small output power source, and is capable of increasing the voltage. The purpose is to obtain a fuel cell capable of

[Means for solving problems]

In the fuel cell according to the present invention, a fuel-side catalyst layer is provided on a part of one surface of a gas-permeable electrode base material, and a part of the other surface of the one-surface part opposite to the part where the fuel-side catalyst layer is not formed. An oxidant-side catalyst layer is provided on the electrode base material, and between the fuel-side catalyst layer and the oxidant-side catalyst layer of the electrode base material and no catalyst layer is formed on either one surface portion or the other surface portion. An electrode body having a gas seal portion, at least second and third electrode bodies having the same structure as the electrode body, and at least two electrolyte holding bodies are provided, and the fuel-side catalyst layer forming portion of the electrode body serves as the first anode. , The oxidant side catalyst layer forming portion of the second electrode body is provided as a first cathode, and the oxidant side catalyst layer forming portion of the electrode body is used as a second cathode. 2 Fuel side catalyst layer formation of the third electrode body with the electrolyte holder interposed The a first anode and the second anode are the same level with to pair set as the second anode,
The first cathode and the second cathode are at the same level, and the first cathode and the second anode are provided with an electrically insulating gas supply plate in which a fuel gas flow path is formed between the anode and the second anode. It is provided with an electrically insulating gas supply plate which extends over two cathodes and has an oxidant gas flow channel formed between the two cathodes.

[Action]

Since the electrode base material in the present invention constitutes the anode on one surface portion and the cathode on the other surface portion with the gas seal portion interposed,
It also has the function of electrically connecting the cells in series. Therefore, the unit cells can be serialized in the same level direction, and the voltage can be increased without increasing the height.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. First
The figure shows a cross section of an anode / cathode body according to an embodiment of the present invention.In the figure, (11a) is a gas-permeable electrode base material, and (2a) is one surface part of the electrode base material (11a). A fuel side catalyst layer provided in a part, (4a) is an oxidant side catalyst layer provided on the other surface portion facing one surface portion of the electrode base material (11a) on which the fuel side catalyst layer (2a) is not formed, (12a) is between the fuel side catalyst layer (2a) and the oxidant side catalyst layer (4a) of the electrode base material (11a), the catalyst layer (2a), (4a) on one surface portion and the other surface portion. In the central portion not formed, both catalyst layers (2a), is a gas seal portion for gas sealing between (4a), the electrode substrate (11a), the fuel side catalyst layer (2a), the oxidant side catalyst layer ( 4a) and the gas seal portion (12a) constitute the electrode assembly A. In addition, the electrode body A constitutes an anode with the fuel side catalyst layer forming portion, for example, the fuel side catalyst layer (2a) and a part of the electrode base material (11a) on which it is formed, and the oxidant side catalyst layer forming portion, for example, The oxidant side catalyst layer (4a) and a part of the electrode base material (11a) on which the oxidant side catalyst layer (4a) is formed constitute a cathode. The anode / cathode body is formed by stacking a plurality of electrode bodies with an electrolyte holding body, for example, an electrolyte holding matrix interposed therebetween. For example, the fuel side catalyst layer (2a) of the electrode body (A)
Is the electrode body with the first electrolyte holding matrix (3a) interposed.
(D) The oxidant side catalyst layer (4d) is opposed to form the first anode / cathode, and the oxidant side catalyst layer (4a) of the electrode body (A) has the second electrolyte holding matrix (3b). In between, electrode body (B)
The second anode / cathode is formed by facing the fuel side catalyst layer (2b). Further, each anode of the plurality of electrode bodies is formed at the same level, and each cathode is formed at the same level. Further, an electrically insulating fuel gas supply plate is formed across each anode of the anode / cathode body, and an electrically insulating oxidant gas supply plate is formed across each cathode to form a fuel cell. ing. Here, the subscripts of each reference numeral indicate the reference numerals common to the materials formed on one electrode base material, and the reference numerals without subscripts are used in general description.

In the fuel cell configured as described above, each anode / cathode forms a unit cell, and the electrode base material (11) functions as each electrode and also functions to connect each unit cell in series. The individual cells are laterally connected in series by a plurality of electrode base materials (11). At this time, one electrode base material
Since the fuel gas and the oxidant gas flow in (11), the gas seal part (12) is provided to prevent the mixture of these. As an example of the gas sealing treatment for the gas permeable electrode base material (11), there is a wet sealing treatment in which the electrode base material (11) is filled with inorganic particles such as zirconium phosphate or phosphorus pentoxide and impregnated with an electrolyte. . Alternatively, a dry gas impermeability treatment in which a packing material or the like is filled may be used.

Fig. 2 shows an example of the ends of the anode / cathode body. (10) is a collector plate, which is the end electrode base material (11) of the cells connected in series and its end. It is in close contact with (13) and collects current.

Since the fuel cells configured as described above can be serialized at the same level, the voltage can be increased without increasing the height.

In addition, in the above-mentioned embodiment, the central portion of the electrode base material (11) has a curvature between both catalyst layers (2) and (4), but as shown in FIG. Even if configured, the same effect can be obtained. The series structure of the unit cells of the present invention is obtained, for example, by arranging the respective members shown in FIG. 1 in a shogi-playing state in the order shown in FIG. . At this time, the electrode base material (11) is flexible such as carbon fiber, and the electrolyte holder (3) is also flexible such that silicon carbide powder is bound with a binder such as polytetrafluoroethylene (PTFE). In the case of the sponge-like one, both members yield and deform when the whole is press-shaped, and as a result, a structure having a curved boundary as shown in FIG. 1 is formed. When the electrode base material (11) has rigidity such as stainless fiber or nickel fiber, the electrode base material (11) is shaped into the shape of (11) in FIG. By performing the press shaping of, a structure having a linear boundary is formed as shown in FIG. At this time, since the electrolyte holder (3) is in the form of a flexible sponge, it is shaped according to the shape of the electrode base material (11) having rigidity.

Further, FIG. 4 shows a cathode / anode body in which, for example, nine electrode bodies are connected in series, and an electrically insulating gas supply plate (13) is provided.
FIG. 3 is a cross-sectional configuration diagram of a fuel cell formed by stacking four layers with the fuel cell interposed therebetween. In this embodiment, the current collector plate (10) and the electric wiring (14) are connected in series in the vertical direction, and a total of 36
A cell battery is connected. Electrically insulating gas supply plate
(13) is a fuel gas flow path for supplying fuel gas to the anode
(9) and an oxidant gas flow path (8) for supplying an oxidant gas to the cathode are constituted, and the stacked cathode and anode bodies are electrically insulated. According to this embodiment, the sixth
The height is the same as that of the conventional fuel cell shown in the figure, and the number of stacked layers is 9 times, and the voltage can be increased. In addition, if the length of the electrode substrate (11) of the desolving electrode body is shortened, a single-stage cathode
The number of series of anode bodies can be increased, and it is compact
You can raise the voltage freely.

Further, the present invention can be applied to all types of fuel cells such as alkaline fuel cells, phosphoric acid fuel cells, and molten carbonate fuel cells.

〔The invention's effect〕

As described above, according to the present invention, the fuel-side catalyst layer is provided on a part of one surface of the gas-permeable electrode base material, and the other surface of the one-side surface facing the part where the fuel-side catalyst layer is not formed is provided. The catalyst layer on the oxidant side is provided in a part of the catalyst, and the catalyst layer is not formed on either one surface or the other surface of the electrode substrate between the fuel side catalyst layer and the oxidant side catalyst layer. An electrode body having a gas seal portion between layers includes at least second and third electrode bodies having the same structure as this electrode body and at least two electrolyte holding bodies, and the fuel side catalyst layer forming portion of the electrode body is One anodic, the oxidant side catalyst layer forming part of the second electrode body is opposed as the first cathode with the first electrolytic layer holder interposed, and the oxidant side catalyst layer forming part of the electrode body is the second cathode. And the fuel side catalyst of the third electrode body with the second electrolyte holder interposed. The forming portion is opposed to the second anode, the first anode and the second anode are at the same level, the first cathode and the second cathode are at the same level, and the first anode and the second anode are straddled. An electrically insulating gas supply plate having a fuel gas channel formed therein, and an electrically insulating gas supply plate having an oxidant gas channel formed between the first cathode and the second cathode and between the cathodes As a result, the cathode and the anode can be serialized in the same level direction, and the voltage can be increased without increasing the height. Therefore, stacking such fuel cells in multiple stages is compact and has the effect of increasing the voltage.

[Brief description of drawings]

FIG. 1 is a sectional view showing a cathode / anode body for a fuel cell according to an embodiment of the present invention, FIG. 2 is a sectional view showing an example of an end portion of the cathode / anode body, and FIG. 4 is a cross-sectional view showing a cathode / anode body for a fuel cell according to the embodiment of the present invention, FIG. 4 is a cross-sectional structural view showing a fuel cell according to still another embodiment of the present invention, and FIG. 5 is a unit cell for a conventional fuel cell. FIG. 6 is a sectional view showing a conventional fuel cell. (2a), (2b), (2c) …… Fuel side catalyst layer, (3a), (3b), (3c) ……
Electrolyte holder, (4a), (4b), (4c) ... Oxidizer side catalyst layer,
(8) …… Oxidant gas flow path, (9) …… Fuel gas flow path, (11a),
(11b), (11c), (11d) …… electrode substrate, (12a), (12b) …… gas seal part, (13) …… electrically insulating gas supply plate, A, B,
C, D ... Electrode body. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (2)

[Claims] 1. A fuel-side catalyst layer is provided on a part of one surface of a gas-permeable electrode base material, and a part of the other surface of the one-surface part opposite to the part where the fuel-side catalyst layer is not formed is oxidized. An agent-side catalyst layer is provided, and both catalysts are provided in a central portion between the fuel-side catalyst layer and the oxidant-side catalyst layer of the electrode base material where the catalyst layer is not formed on one surface portion or the other surface portion. An electrode body having a gas seal portion between layers, at least second and third electrode bodies having the same configuration as the electrode body, and at least two electrolyte holding bodies are provided, and the fuel side catalyst layer forming portion of the electrode body is The first oxidant side catalyst layer forming portion of the second electrode body is the first anode, and the first electrolyte holding body is interposed therebetween.
As a cathode, the oxidant side catalyst layer forming portion of the electrode body serves as a second cathode, and the fuel side catalyst layer forming portion of the third electrode body serves as a second anode with a second electrolyte holder interposed. The first anode and the second anode are at the same level, the first cathode and the second cathode are at the same level, and the fuel gas flow path is formed between the anode and the second anode. Fuel cell having an electrically insulating gas supply plate provided with the electrically insulating gas supply plate, and an electrically insulating gas supply plate having an oxidant gas flow path formed between the first cathode and the second cathode and between the cathodes. 2. The fuel cell according to claim 1, wherein the gas seal portion is a wet seal portion in which the electrode base material is filled with inorganic particles and impregnated with an electrolyte.